Old HotRodder

[50sFlash]

I have to confess, I don't race boats, although I have watched a couple on the Mississippi up here in Minnesota. I am an old racer though. This was my last race car in 1970
http://i256.photobucket.com/albums/hh181/50sflash/Camaro2.jpg
About 8 years ago I discovered classic fiberglass boats, and had to jump in. My first was a 58 Glastron FireFlite with a 75 Johnson. I made it into a hot rod with rolled and pleated interior, and lace paint. I hopped it up by putting a 50 horse hood on it.
http://i256.photobucket.com/albums/hh181/50sflash/0705_025.jpg
Then a 75 Larson All American http://i256.photobucket.com/albums/hh181/50sflash/DSC02036.jpg
with a 35 Johnson
http://i256.photobucket.com/albums/hh181/50sflash/DSC02029.jpg
and now I'me working on a 59 Classic Barricuda that I'm putting 2 35 Johnsons on.
http://i256.photobucket.com/albums/hh181/50sflash/DSC02195.jpg
Well maybe I should just rebuild them and leave them alone, but the hotrodder in me says "there must be a few more horses in there just waiting" I looked through the great web and ended up here. I read about the two-cycle tuners hand book and looked for one to buy. I found one in great condition for $999. More knowledge than I wanted. But after reading a little more found one to download, but the math is a killer. I really don't need to go that fast!!!

Here's my question to the experts. I want to mill the head, How much can I take off without turning it into a race motor? If I oval out the exhaust port how much? I want a couple good running motors that stay together, but give me a little more punch. Or should I just leave well enough alone?

I hope someone has an answer for an old hotrodder.

[Mark75H]

You can do a lot to the motors, but the limiting factor is their lower unit.

[JohnsonM50]

I have to confess, I don't race boats, although I have watched a couple on the Mississippi up here in Minnesota. I am an old racer though. This was my last race car in 1970
http://i256.photobucket.com/albums/hh181/50sflash/Camaro2.jpg
About 8 years ago I discovered classic fiberglass boats, and had to jump in. My first was a 58 Glastron FireFlite with a 75 Johnson. I made it into a hot rod with rolled and pleated interior, and lace paint. I hopped it up by putting a 50 horse hood on it.
http://i256.photobucket.com/albums/hh181/50sflash/0705_025.jpg
Then a 75 Larson All American http://i256.photobucket.com/albums/hh181/50sflash/DSC02036.jpg
with a 35 Johnson
http://i256.photobucket.com/albums/hh181/50sflash/DSC02029.jpg
and now I'me working on a 59 Classic Barricuda that I'm putting 2 35 Johnsons on.
http://i256.photobucket.com/albums/hh181/50sflash/DSC02195.jpg
Well maybe I should just rebuild them and leave them alone, but the hotrodder in me says "there must be a few more horses in there just waiting" I looked through the great web and ended up here. I read about the two-cycle tuners hand book and looked for one to buy. I found one in great condition for $999. More knowledge than I wanted. But after reading a little more found one to download, but the math is a killer. I really don't need to go that fast!!!

Here's my question to the experts. I want to mill the head, How much can I take off without turning it into a race motor? If I oval out the exhaust port how much? I want a couple good running motors that stay together, but give me a little more punch. Or should I just leave well enough alone?

I hope someone has an answer for an old hotrodder.
Thats a cool boat. Those older 35s were a good running long lasting motor but were not real fast. Even so theres alot of motor on board so you could leave em stock, work on set up, hull drag & weight. Those will get you a little but the biggest increase would be from props. Being that you need 2 is more of a challenge to find. With 2 motors you could technically spin a prop pitched for near 70 hp. Since if you had a 70 it would spin 1 prop somewhere less would be a happy medium. You would most likely need to have custom mades for the lack of availability or just get the hi-est pitch stock props made. If possible youll want $tainless steel, will out run & accelerate a comparable aluminum 1. With some work & testing you should get into the 40s no problem, maybe more all things being optimal. With 2 props spinning the same way you will want to watch for handling issues like it wanting to bite real hard it a left turn. [unles they counter rotate] Good Luck, Mike

[Mark75H]

Those will get you a little but the biggest increase would be from props. Being that you need 2 is more of a challenge to find. With 2 motors you could technically spin a prop pitched for near 70 hp. Since if you had a 70 it would spin 1 prop somewhere less would be a happy medium. You would most likely need to have custom mades for the lack of availability or just get the hi-est pitch stock props made.

Even custom made high pitch props will not overcome the shortcomings of the poor shape of these lower units.

[JohnsonM50]

Even custom made high pitch props will not overcome the shortcomings of the poor shape of these lower units.Yeah their not that streamlined but my experience with that type motor is that from an average set up starting point -some- improvement can be realized.. If set less deep w/ better more pitch less dia. props. Theres no shortage of torque either to go with.

[Mark75H]

Mike, these are completely insensitive to how deep they are, they are that bad.

[Skoontz]

Cool looking boats. If you want to mill the heads of your 35's, you can safely take .040 from most of the pre 1970 motors, but, don't use that as etched in stone. Get some modeling clay, or soft lead, run the pistons to TDC, then mic the clay of soft lead. We have taken .100 from some heads where others .040 is as close as you want to be.

But, I echo what Sam said about the hydro dynamics of the gear cases on those motors. Without doing something there, anything you do up top will be insignificant.

[JohnsonM50]

Mike, these are completely insensitive to how deep they are, they are that bad.
I cant argue that they arent that bad, as is.. they are. I have done work with one similar, starting out at 34 on a utility & eventually got 46 from it [same boat]. By then it was thinned to the breaking point & I put a cone on it. It also has a speed prop adapted. Definitly not the same as what I started with but the same hunk of junk- changed a little ;). Very limited as you say tho, running the powerhead above 6200 helped a little too.

[50sFlash]

Thanks guys. I'm use to Merc guys dissin' my Johnsons, but I don't have any Speedmaster units for them, so we "run what ya brung" I have a 16 1/2" transom. I worry about going higher because I don't want remote water pick-up. I have a friend that has a prop shop and will bend the aluminum ones till I find something special cheap. (cheap is the important part) and a friend with a company called "Metals Joining Lab" He can weld anything, so I could add a nosecone. Sounds like that might help.
How much piston to head clearance should I have? The pistons are so far down I can't believe there's any amount that could bring them too close. I have also seen "hi compression" head gaskets. Are there different thicknesses? How about "cleaning up" the ports?
You guys are great.
Thanks
Jerry
http://i256.photobucket.com/albums/hh181/50sflash/0705_033.jpg

[JohnsonM50]

Thanks guys. I'm use to Merc guys dissin' my Johnsons, but I don't have any Speedmaster units for them, so we "run what ya brung" I have a 16 1/2" transom. I worry about going higher because I don't want remote water pick-up. I have a friend that has a prop shop and will bend the aluminum ones till I find something special cheap. (cheap is the important part) and a friend with a company called "Metals Joining Lab" He can weld anything, so I could add a nosecone. Sounds like that might help.
How much piston to head clearance should I have? The pistons are so far down I can't believe there's any amount that could bring them too close. I have also seen "hi compression" head gaskets. Are there different thicknesses? How about "cleaning up" the ports?
You guys are great.
Thanks
Jerry
http://i256.photobucket.com/albums/hh181/50sflash/0705_033.jpgDont worry, Johnrudes are good for different reasons aaannd there may be a few that are faster than their Merc counterpart. :cool:

[Mark75H]

I agree, there are a lot of OMC models that are greatly superior to motors Merc sold to compete with them in particular power ranges over the decades.

[Skoontz]

Remember, if you are not driving an OMC, you ain't got no Johnson! One thing your 75 will do that no Merc in it's age and class will do....Pull 6 skiers out of the water at one time and maintain 28-30MPH. But I'll tell yopu a story about a 75HP Johnson against a pair of Merc 1000's with speedmasters on a Switzer Catamaran........Dateline St. Charles Illinois, 1965. Dad installed a 75 Rude on a 14' Yellow Jacket and then went to Carl Stirn's Marine and bought a 17" Johnson-Oakland prop for it because the 15" was not big enough.... The race was about 5 miles long with a turn at the 2.5 mile mark, then back to our boat house. The boats rounded the turn by the gold course about 1/2 mile up river from the boathouse. You could hear the Mercs winding tight and then thr throaty sound of the V-4 side by side. My dad pulled next to the Mercs and waited until he had no more...One of the mercs buddies saw what was going on and went up front by the park with his Chris Craft inboard making waves in hopes the Cat would cut through them, while the rounded bottom of the Yellow Jacket would get tossed all over the place....

What he did was in fact create a situation where for 100 yards, the Yellow Jacket rose over the waves on a sheet of spray and air sort of like a hydro runs. At that point, the Yellow Jacket shot out so far in front it was emarrassing to the Merc. A photo of that race was given to Lou Eppel the former service manager of Johnson and it sat on his desk for a number of years.

[50sFlash]

I had a chance to hear Bob Switzer talk about how the flying wing evolved. I believe you Bill, but if I had to choose between a set-up Switzer, and a plywood Yellow Jacket with any motor - - - well.
http://i256.photobucket.com/albums/hh181/50sflash/849.jpg

I'm in the process of installing a Hot Foot for my twins. The tech guy at T-H Marine says he doesn't think it will work. I didn't tell him I was an old hotrodder, and could make almost anything work. we'll see.
I have a question about compression. The pistons are down in the hole about 1/4". If I cut the piston dome, say about .060, and cut the deck around .100 that would bring the mass of the piston up .040. More compression without disturbing the flame pattern by reducing the combustion chamber a bunch. How about fly-cutting for spark plug clearance?

[Mark75H]

That would make more power, but doesn't solve the other issue.

[JohnsonM50]

I had a chance to hear Bob Switzer talk about how the flying wing evolved. I believe you Bill, but if I had to choose between a set-up Switzer, and a plywood Yellow Jacket with any motor - - - well.
http://i256.photobucket.com/albums/hh181/50sflash/849.jpg

I'm in the process of installing a Hot Foot for my twins. The tech guy at T-H Marine says he doesn't think it will work. I didn't tell him I was an old hotrodder, and could make almost anything work. we'll see.
I have a question about compression. The pistons are down in the hole about 1/4". If I cut the piston dome, say about .060, and cut the deck around .100 that would bring the mass of the piston up .040. More compression without disturbing the flame pattern by reducing the combustion chamber a bunch. How about fly-cutting for spark plug clearance?

My experience with raising the compression on deflector OMCs is that you will gain acceleration mostly but that extra can be applied to more prop [again preferably SS]. As far as the 'foot print' its still a problem but if it will get out of its own way off the line & go a little faster, not a bad thing. :cool: I can also tell ya that sure more motor will get ya there but if your willing to put time into what you have you can improve it. Good Luck.

[Skoontz]

I'm thinking you are approaching this thing in reverse of the way you should.

I would fist do everything you can to maximize the hydro dynamics and bottom of the boat. Things like if you have a hook, if the transom does not have a perfect angle to the bottom and is curved ( thast needs to be a hard angle) things like that.

Once you gain from below, then go up top. If you do too much at once, you may end up not seeing much. Kind of like dropping a 572 Chevy crate motor in a Chevelle without adding a good set of ladder bars...Jump on it hard off the line, and it is going to bunny hop all over.

In that application, you would do suspension work forst, tranny, rear end, traction control devices, then the big motor.'

Same thing on the water.

The story I passed along was just a couple guys out river racing with run what they brung situations. If you want to see what a 75HP OMC can really do in stock form with just lower unit and a good boat, see if you can find the footage of the Star Flight Too, which was a box stock 89.9 cubic inch OMC engine, with a racing gear case. The boat ran around 117? give or take. That will give you the idea of what we are talking about here. All the mods were below the water.

[50sFlash]

The pictures I saw of star flight too was a highly modified motor with carbs on the side on the defuser plates.
I have done the hull. New floor, stringers and transom. There's no hook or hog. That's just fine, and there's nothing I can do about the aerodynamics of the lower unit.
http://i256.photobucket.com/albums/hh181/50sflash/295.jpg
http://i256.photobucket.com/albums/hh181/50sflash/479.jpg

I want to know if anyone has cut the deck, rather than mill the heads on a 2 cylinder OMC. I can't be the first guy to think about this.

[JohnsonM50]

The pictures I saw of star flight too was a highly modified motor with carbs on the side on the defuser plates.
I have done the hull. New floor, stringers and transom. There's no hook or hog. That's just fine, and there's nothing I can do about the aerodynamics of the lower unit.
http://i256.photobucket.com/albums/hh181/50sflash/295.jpg
http://i256.photobucket.com/albums/hh181/50sflash/479.jpg

I want to know if anyone has cut the deck, rather than mill the heads on a 2 cylinder OMC. I can't be the first guy to think about this.

Ive heard of it being done but havent myself. The OMCs Ive got the pistons come to the top of the bore so the heads the way on em.

[50sFlash]

Thanks Mike, I was surprised to see the pistons not come to the top. I hope this shows it OK. This is at TDC. Still looking for someone that has run these before.

http://i256.photobucket.com/albums/hh181/50sflash/DSC02544.jpg

I got the Hot Foot ready with both cables. It doesn't return well, but I think after the motors are rebuilt and the advance freed up it should be OK.

http://i256.photobucket.com/albums/hh181/50sflash/DSC02540.jpg

http://i256.photobucket.com/albums/hh181/50sflash/DSC02542.jpg

[Skoontz]

Actually, they went to great lengths to make a power head adapter plate and stack that bolted to the bottom of the block, so they could run a basically stock power head. The vast majority of the work was in the Hubbell over drive gearcase and the tower. When the record was set the engine was only turning 4900 RPM.

What is your goal by decking a block, are you looking for more RPM? Torque? There will come a point where you can't push the bottom end any faster no matter what you did on top.

Don't get me wrong here, it looks like a fun venture, I just hate to see anyone sink allot of time and money into something that will need even more money to make it really work at it's best.

[50sFlash]

I just want a little more horsepower out of them, without making them run WOT all the time. I think more compression is the key to that. They have something like a 5 to 1 compression ratio. I really don't want to spin them over 5 grand. I just want to get a couple more inches of pitch and go fast and look good. This is basically a show-boat. Speaking of shows, anybody from this group going to Muscatine? www.muscatineboatshow.com.

[JohnsonM50]

Thanks Mike, I was surprised to see the pistons not come to the top. I hope this shows it OK. This is at TDC. Still looking for someone that has run these before.

http://i256.photobucket.com/albums/hh181/50sflash/DSC02544.jpg

I got the Hot Foot ready with both cables. It doesn't return well, but I think after the motors are rebuilt and the advance freed up it should be OK.

http://i256.photobucket.com/albums/hh181/50sflash/DSC02540.jpg

http://i256.photobucket.com/albums/hh181/50sflash/DSC02542.jpg
Yeah, thats pretty low in the hole. The 70s deflectors I play with have a very close fitting piston/head situation compared. Hot foot: you could separate the timing & the throttle, I do it by spring loading the time w/ a 2 position setup w/ adjustable full advance. In other words I start it retarded & run it full. I use a Quincy safety throttle, it doesnt have enough throw or return spring to operate both time & throttle. The hot-foot probably has more capacity. Being determined to get what you want is cool, You can do it! :cool: Show & Go are cooler than Show or Go:cool:

[Mark75H]

If you want to see what a 75HP OMC can really do in stock form with just lower unit and a good boat, see if you can find the footage of the Star Flight Too, which was a box stock 89.9 cubic inch OMC engine, with a racing gear case. The boat ran around 117? give or take. That will give you the idea of what we are talking about here. All the mods were below the water.

The average speed turned out to be 114+

I don't think OMC claimed anywhere that the powerhead was box stock ... all that was box stock was the 5,000 rpm motor speed. You have to listen closely to advertising claims and recall every detail.

[Skoontz]

It would be very interesting to see if anyone on that project was still alive and might remember details, or better yet, if the motor was stilll around....

[Mark75H]

The motor is still around, but I doubt anyone would be allowed to check the specs on it.

[Skoontz]

I would settle for a few pictures similar to what was taken of the Starflite IV's engine.

[Mark75H]

I would settle for a few pictures similar to what was taken of the Starflite IV's engine.


IV's engine? In a museum or magazine?

[50sFlash]

The motor is still around, but I doubt anyone would be allowed to check the specs on it.

Ya think maybe she's not quite stock Sam?

[Skoontz]

I saw a video of Doc Jones taking about the engine...He ays, "block's stock, crank and rods are stock, heads are stock, everything except the exhaust and lower unit."

Now who knows if that was what just what was said and not what was...

The Starflite IV engine resided in the Briggs basment up in Lake Forest IL? I thought, but there have been some pretty extensive close up photos where unlike the Starflite 2 and 3 motors.

You know who would know if he can be found is the Mouse.

[50sFlash]

I've been racing since 1959. I know there's three things you need to do to go fast. Increase air flow, increase compression, decrease reciprocating mass (burn more gas than the next guy). Show me the fool that wants to set the speed record and doesn't do that, and I'll show you somebody that won't set the record.

[JohnsonM50]

I've been racing since 1959. I know there's three things you need to do to go fast. Increase air flow, increase compression, decrease reciprocating mass (burn more gas than the next guy). Show me the fool that wants to set the speed record and doesn't do that, and I'll show you somebody that won't set the record.
Having started in the auto trades & having worked a few non race hotrod Mopars for myself, that is what ya want. For these 2 strokes it seems the trick is to speed up induction by "padding" rather than volumizing as you would a 4 stroke. All motors being different you might not want to increase the crankcase volume between the reeds & the pistons. If you take the reeds out & look bacwards thru the reed plate, intake & out the carb you may see some miss-matching of parts to clear up.
http://i35.photobucket.com/albums/d151/mes355/DSCN0091.jpg
http://i35.photobucket.com/albums/d151/mes355/DSCN0088.jpg
This is what youll find in a typical 22ci/31.8ci OMC yours will probably be similar. Will it help? I think it does but not significant.

[50sFlash]

Thanks Mike. I think it's all about how much air/fuel mix you can get into the cylinder at the bottom of each stroke. Maybe I'm missing something about 2 strokes, because you are trying to compress that mixture in the crankcase to force it into the cylinder, so maybe building compression (less area) in the crankcase does more than increased compression in the cylinder. Does it help? I raced small-block chevs for years. I ran a 14 to 1 compression and shifted at 10,000 RPM. Every little thing helps. so when I see a low compression motor I want to change it. Old habits ya know. I would love to what I would call valve timing, raising the port height to open them sooner, but I'm afraid I'm already over my head. I don't want a monster that won't idle, or run slow in a "no wake" zone (we have a lot of those). Here's my "non race" Mopar. We take the boats to car shows with it.

http://i256.photobucket.com/albums/hh181/50sflash/DSC01936.jpg

Jerry

[JohnsonM50]

Thanks Mike. I think it's all about how much air/fuel mix you can get into the cylinder at the bottom of each stroke. Maybe I'm missing something about 2 strokes, because you are trying to compress that mixture in the crankcase to force it into the cylinder, so maybe building compression (less area) in the crankcase does more than increased compression in the cylinder. Does it help? I raced small-block chevs for years. I ran a 14 to 1 compression and shifted at 10,000 RPM. Every little thing helps. so when I see a low compression motor I want to change it. Old habits ya know. I would love to what I would call valve timing, raising the port height to open them sooner, but I'm afraid I'm already over my head. I don't want a monster that won't idle, or run slow in a "no wake" zone (we have a lot of those). Here's my "non race" Mopar. We take the boats to car shows with it.

http://i256.photobucket.com/albums/hh181/50sflash/DSC01936.jpg

JerryExcellent, My favorite 'owned' Mopar was a 65 Barracuda-273 Formula S w/some direct connection goodies. Having worked at a Chry-Ply dealer I got to drive almost all the factory street rods of the late 60s early 70s, not realizing then the value of that opportunity. But yes 2 strokes.. not only different but ea. different so to say some Mercs are "padded" doesnt mean OMCs should or need to be. [dont know] Theres 4 compressions in your motors, crankcase & combustion. Increasing CC volume might decrease that compression so in theory Id guess by speeding it up one accomplishes the more thing. Only as much air as can pass thru the carb & reeds is going in anyway & this is also the lube so pressure is critical. If Im wrong here... somebody'll kick it in the butt...::eek::D

[50sFlash]

In '64 I bought a new Polara Convert with a 426 wedge. It soon caught the eye of a sweet young thing that wanted to drive it. We traded it in '68 for a new charger with a 318. She is still driving my toys 43 years later.

http://i256.photobucket.com/albums/hh181/50sflash/48Plymouth-16.jpg

[JohnsonM50]

In '64 I bought a new Polara Convert with a 426 wedge. It soon caught the eye of a sweet young thing that wanted to drive it. We traded it in '68 for a new charger with a 318. She is still driving my toys 43 years later.

http://i256.photobucket.com/albums/hh181/50sflash/48Plymouth-16.jpgCool, My wife wants little to do with my go-fast junque, least of all a ride or drive. :eek:;)

[50sFlash]

OK, a bunch of people look, but I need more input, How about Boyesen valves? Money well spent ($175) or save it for filling the gas tank? Has anybody ever raced these motors? Still nobody going to Muscatine?
Talk to me people!

[Mark75H]

Has anybody ever raced these motors?

They have never been used in a racing class that allowed modification

[jeff55vDSH]

Thanks guys. I'm use to Merc guys dissin' my Johnson

You have a small Johnson.

Just kidding. Ages ago, my Dad sooped up an 'ol 35 rude with a Jet Pack carburator on the intake bypass ports of the motor. He says it was good for a small gain.
Back then, 35hp was about the biggest outboard they had. I think he ran it on a little switzercraft.
Hey, I'll be at the Muscatine boat show again this year. I just have some newer racin' stuff to display, maybe I'll test if the water's not flooding this year. See you there?

[50sFlash]

You have a small Johnson.

Just kidding. Ages ago, my Dad sooped up an 'ol 35 rude with a Jet Pack carburator on the intake bypass ports of the motor. He says it was good for a small gain.
Back then, 35hp was about the biggest outboard they had. I think he ran it on a little switzercraft.
Hey, I'll be at the Muscatine boat show again this year. I just have some newer racin' stuff to display, maybe I'll test if the water's not flooding this year. See you there?

I hope so Jeff. Last year was a mess. Dave says there will be no floods this year, so maybe I'll get mine in too. You will have to come down to the show end. I'll have the motorhome there and a cold one. Is your Dad still around?

http://i256.photobucket.com/albums/hh181/50sflash/23.jpg

[50sFlash]

I found an easy 5 bolt-on horses.

http://i256.photobucket.com/albums/hh181/50sflash/DSC02555.jpg[/img]

http://i256.photobucket.com/albums/hh181/50sflash/DSC02556.jpg

I was told the 40 is a better powerhead to modify because it has bigger crank journals. Thoughts anyone?

[JohnsonM50]

I found an easy 5 bolt-on horses.

http://i256.photobucket.com/albums/hh181/50sflash/DSC02555.jpg[/img]

http://i256.photobucket.com/albums/hh181/50sflash/DSC02556.jpg

I was told the 40 is a better powerhead to modify because it has bigger crank journals. Thoughts anyone?

I dont know about the crank but typical of johnny-rude to put a different crank in a motor that looks outwardly the same as another.. Ive got 2 31.8 35s apart, 1 has a better crank but I found the labrynth seal to be bigger on 1, same otherwise.
Got a Lark 35 & a '60 40 like yours, on the same boat the 40 had a slight acceleration edge but no top speed increase.
Ive thought also about the reeds, been told "not worth it", "well worth it" & "if one breaks your motor wont get hurt". What I do know is that experimenting with reeds makes a difference.. I made a jig to bend stops a little, got a little performance, bent some more & got a new piston. They will break but till then the motor will do 3-5 hundred Rs more under the same load. Thats an argument for trying composites but I havent $prung for em yet...Or discovered my being a long lost Rocker-feller. lols

[JohnsonM50]

I dont know about the crank but typical of johnny-rude to put a different crank in a motor that looks outwardly the same as another.. Ive got 2 31.8 35s apart, 1 has a better crank but I found the labrynth seal to be bigger on 1, same otherwise.
Got a Lark 35 & a '60 40 like yours, on the same boat the 40 had a slight acceleration edge but no top speed increase.
Ive thought also about the reeds, been told "not worth it", "well worth it" & "if one breaks your motor wont get hurt". What I do know is that experimenting with reeds makes a difference.. I made a jig to bend stops a little, got a little performance, bent some more & got a new piston. They will break but till then the motor will do 3-5 hundred Rs more under the same load. Thats an argument for trying composites but I havent $prung for em yet...Or discovered my being a long lost Rocker-feller. lols
Something more to consider, The shrouding on those is so tuff & bulky youd think they were bullet proof, Your best performance trick may be 'safely' losing some weight... [from it lols]

[jeff55vDSH]

Something more to consider, The shrouding on those is so tuff & bulky youd think they were bullet proof, Your best performance trick may be 'safely' losing some weight... [from it lols]

Oh...but those oldies were SO quiet with that extra shrouding! Seriously. Undoubtebly the quietest motor of that era.
But I agree, the extra shrouding added about 25lbs to them.

[Skoontz]

Mike:

We had some issues with 40HP rods that we never had with 30/33/35's...If memory serves me, there were a couple years where the rods were weak, just as with the first year 75 V-4's. Changes were made, though I cannot tell you what and how. That said, check the part numbers to see if they were the same, or, maybe Michael G can chime in if he is out there, I could be off base here.

[JohnsonM50]

Oh...but those oldies were SO quiet with that extra shrouding! Seriously. Undoubtebly the quietest motor of that era.
But I agree, the extra shrouding added about 25lbs to them. Thats right, my 40 even has Super Quiet decal-ed onto the mid, even the mid has a shroud & the front half seconds as the lower mount- hard to lose that.

[50sFlash]

OK when I pulled the powerhead I found spring and seal parts. Is there such a thing as heavy duty?

What's the little valves for? Is just stock OK? new or run what I got?

http://i256.photobucket.com/albums/hh181/50sflash/DSC02560.jpg

[JohnsonM50]

OK when I pulled the powerhead I found spring and seal parts. Is there such a thing as heavy duty?

What's the little valves for? Is just stock OK? new or run what I got?

http://i256.photobucket.com/albums/hh181/50sflash/DSC02560.jpg Believe it or not those are compression releases to start it.

[JohnsonM50]

Believe it or not those are compression releases to start it. OOps, I just stumbled down & didnt even have coffee yet. those are in the back by the spark plugs. I think my coffees done :D

[50sFlash]

That's OK Mike, April Fools Day was Wednesday. Ya didn't fool me. LOL One has a large hole under it, the other has like a 1/16" hole. Since I can't even find a listing for Boyesen valves for this thing I guess it doesn't matter what they do. The top cylinder had a sticky top ring and blow-by scuffing, and residue in the intake side, but the ring lands are good, so I think it will clean up OK. All the bearing surfaces are good. Who sells cheap parts?
One other thing, I thought it had a 3" bore, but it measures like 3.060 with my cheap calipers. I couldn't have a 60 0ver stock from factory could I?

[JohnsonM50]

I dont know about the bore, biggest over Ive seene was 40 over for the 31.8ci. Best bet on parts is spare motors but some stuff should be new. Look up the Mastertech, if he has em itll be reasonable.

[mac19f]

The first year 40hp engine(1960) had a weak crank. Johnson offerred to replace all of the powerheads under warrantee with the next year's powerhead with a stronger crank. Some people did; some didn't.

The two little valves are crankcase puddle drains. The lower seal is carbon. It has an o-ring inside that should be replaced. If the carbon itself is not broken or scarred it can be reused.

[Mark75H]

The two little valves are crankcase puddle drains.

Thanks Greg

I thought that's what those are, but not being an expert on that motor, didn't want to say so. Is that what made these motors famous for leaving a sheen on the water?

[50sFlash]

Thanks Greg. That's almost obvious when you look at it and think. It doesn't vent to the atmosphere Sam, I think the oil slick came from running 25 to 1. There's a ton of carbon build-up in this one. Well I got a bunch of Dremel work to do. Ahhhh the smell of grinding cast iron. It's right up there with resin and nitro.

[Mark75H]

It goes down into the leg doesn't it?

[50sFlash]

There's a cover and gasket. I think it comes out, and goes back into the intake side.

[JohnsonM50]

There's a cover and gasket. I think it comes out, and goes back into the intake side. Thats the idea, to burn it off in the top cyl. [I think]
The bore is 3 3/16, stroke 2 3/4. @ 43.9ci 4-5G run range 40hp @ 4500. Gears- 12:21 dont think there was an option, 10 3/8 dia X 13 1/4 pitch hi-est pitch in book but I think you could do better. Point gap 0.020- all, plug gap 0.030 [ I found the book but it doesnt cover the 35, probably-mostly the same.

[Skoontz]

When setting points on any 1951-1976 OMC, you will get the best job by not using a feeler guage.

You are best using the factory timing fixtures and snugging them on the crank.

Then you use a timing light, i.e. a flash light that needs alligator clips and wire to make a connection. You clip one wire to the mag plate, then the other wire to the screw on the point where the condenser wires attach. Before you turn on the juice, disconnect the ground wire to the coil and leave it hang. You don't want to run any juice through the coils. If you cannot find this type of light, an electrical testing meter works too, I just like the light better.

Rotate the engine so the point set you are gapping are the point set for the correct cylinder. Place the pointer of the timing fixture between the cast in hash marks on the front of the mag plate. Screw the cam screw on the points back or fourth to get the light to flicker. Then once the light goes off, move the crank gently back and fourth over the hash marks and see where the light goes out. Ideally, you want no light as the timing fixture exits the hash marks.

Follow the same thing on the next set of points. Remove the fixture, screw back down the coil grounds and torque the flywheel back down.

I have two complete sets of these fixtures from OMC, and there is a guy who makes them on the AOMCI website for $35 each. Not only will they save time, they will be far more accurate than any feeler guages you use.

[JohnsonM50]

When setting points on any 1951-1976 OMC, you will get the best job by not using a feeler guage.

You are best using the factory timing fixtures and snugging them on the crank.

Then you use a timing light, i.e. a flash light that needs alligator clips and wire to make a connection. You clip one wire to the mag plate, then the other wire to the screw on the point where the condenser wires attach. Before you turn on the juice, disconnect the ground wire to the coil and leave it hang. You don't want to run any juice through the coils. If you cannot find this type of light, an electrical testing meter works too, I just like the light better.

Rotate the engine so the point set you are gapping are the point set for the correct cylinder. Place the pointer of the timing fixture between the cast in hash marks on the front of the mag plate. Screw the cam screw on the points back or fourth to get the light to flicker. Then once the light goes off, move the crank gently back and fourth over the hash marks and see where the light goes out. Ideally, you want no light as the timing fixture exits the hash marks.

Follow the same thing on the next set of points. Remove the fixture, screw back down the coil grounds and torque the flywheel back down.

I have two complete sets of these fixtures from OMC, and there is a guy who makes them on the AOMCI website for $35 each. Not only will they save time, they will be far more accurate than any feeler guages you use.
It is a little touch & go [do it again] w/a feeler but at least on the 40 you can do it thru the acc. hole.... didnt know you were a teeker Bill:cool:

[Mark75H]

My father built himself some tools like this and built for OMC motors, some of the long pointer type tools Merc supplied to their dealers. He was not impressed with the results over using a feeler gage.

[50sFlash]

You are best using the factory timing fixtures and snugging them on the crank.

I have two complete sets of these fixtures from OMC, and there is a guy who makes them on the AOMCI website for $35 each. Not only will they save time, they will be far more accurate than any feeler guages you use.

Bill, We used a beeper, or an Ohm meter to set the timing on the dragster. I understand that. Who sells the fixture? or do you want to part with one of yours. (sound like ya got one to crap on, and another one to cover it up with) Does that hold the advance plate at the right spot for timing, or just setting the points?

Jerry

[JohnsonM50]

Bill, We used a beeper, or an Ohm meter to set the timing on the dragster. I understand that. Who sells the fixture? or do you want to part with one of yours. (sound like ya got one to crap on, and another one to cover it up with) Does that hold the advance plate at the right spot for timing, or just setting the points?

Jerry Hey Jerry, I shoulda mentioned before, if you go to AOMCI, then on the left under 'Everybody' theres free adds, might find anything but its alot to go thru. Placing a wanted is free too. Your welcome to join & theres the ask a member section [also for everyone]. There you might find alot of book knowledge of your motors but for the goods on go -fast stay- tuned- right here where its:cool:;)

[Skoontz]

Jerry:

Can't part with dads tools! If you go to AOMCI and into the ads, they are free ads...Post what I said, and add your e-mail and phone to the bottom. If you are not a member it will not bring it up for you.

They guy who makes them is in Florida and he should hook up with you.