need help 50hp merc

[Arkansas river rat]

I have a 1980 50hp merc. I going to use a 1976 50hp midsection and drive shaft to change it to a short shaft. The wiring on the 76 has fallen apart. The motor has good compression tho. I plan on running a chopper prop on the motor when i have the prop lower unit on. I'm going to put the motor on my 1648 jon boat that weighes around 350ibs if not lighter. Do i need to run a lower water pickup? If so were can i find one? I've found low water pickups but they are all for bigger outboards than mine. I run the boat light and i'll have a tiller on the motor. I'd like to make the boat run like a scolded ape lol Can i modify the 1976 50hp to run a little harder? While i get by on the other 50hp merc or my 25hp merc. The 25merc pushes the boat around 30 mph maybe faster if i ran a 14pitched prop instead of the 13. I just don't know about the motor design. I'm used to having a head that i can mill down to raise compression and boring out carbs or replacing them.

[Arkansas river rat]

I've been reading Doug Kay builds merc 44 . I wonder if he could build the 1976 44 merc for me just for playing on the river. Doesn't take long to switch powerheads. Does anyone know what type of mods to do the the powerhead and a price estimate?

[formeone]

biggest thing put merc 1-1/16th carbs on..deff improvement... time it at .215 before top dead,,,run boysen dual stage reeds,,, and the aluminum reeds, put 100hp reed stops on them grind to a bevel at leading edge,,,and port it prob about 30-40 thousands for ya that way still get torque... other than running pipes on it that about it,,,, could drill out exhaust in center section to allow more exhaust out..

[A/B Speedliner]

Doug Kay does great work, he has produced some winning engines for us. His contact info is 586-212-5917

David Van Weele

[Mark75H]

I'd be interested to hear how this works out

[Fastjeff57]

..."aluminum reeds, put 100hp reed stops on them grind to a bevel at leading edge.."

Aluminum reeds? And what leading edge is one to grind a bevel on?

Thanks,

Jeff

PS: On that rotted out wiring--what the heck were they using for wiring back then?--the only fix is to take one wire at a time, follow it back to where hopefully enough is left to get hold of, and replace it (with the same color wire or Oh my God will you have trouble.)

[A/B Speedliner]

I think he meant Alumin. reed cage and to grind the front edge of the reed stop so he could bend them up to allow the reed stop to be bent up. That way the stop will not hit the crank. That is just my quess?

David

[formeone]

correct speedliner,, plus of course boysen reeds,,,,,i have tried lots of reeds and designs over the years,,,, the best where boysen,,, and of course hustler puipes,,,, if ya can find them,,,

[clough]

biggest thing put merc 1-1/16th carbs on..deff improvement... time it at .215 before top dead,,,run boysen dual stage reeds,,, and the aluminum reeds, put 100hp reed stops on them grind to a bevel at leading edge,,,and port it prob about 30-40 thousands for ya that way still get torque... other than running pipes on it that about it,,,, could drill out exhaust in center section to allow more exhaust out..

running the same motor but 40hp (newer style 44ci) you mentioned 1-1/16th carbs are those carbs off of another motor if so what motor?

[Arkansas river rat]

So use aluminum reed cages and boysen. reeds and use 100hp reed stops after grinding them down on the leading edge . Can i just bore out the carbs? or can i find a set easy? What motor year hp can i get a set off of.

[formeone]

thinke the carbs off of merc 650 or?? not sure on witch motor for sure,,,
most the d-mod/750 guys raceing have them on there motors,,, they are 50 hp but have stacks soo prob have to jet down abit we on the west coast usually run .067 jets in them soo prob a bit smaller,,, maybe .064??,,, cant bore the original carbs that much

[A/B Speedliner]

I went into my carb collection and find the KC14A is 1-1/16". I only have one.

I found a pair of 1-3/16" carbs in the pile.

David

[Arkansas river rat]

Would 1 3/16 carbs be over carbing the motor? I'm at 1100 elevation here in Arkansas . I can carb a dirt bike if i can start from a good idea which way i need to jet it. i can dial it in. Dirt bikes are alot different than outboard motors but jetting it shouldn't be that hard. I think i can learn alot from all of you guys on here. I've got to old for bikes and know boats are my hobby. I have the need for speed lol. Just no racing really goes on around were i live. Can you not just by high dome pistons for a motor instead of padding the cylinder head? thinking about fabing a few exuast tubes to kinda act like an expansion chamber in the midsection . The tube seems really restrictive and there is all kinds off room in the midsection to make the tube bigger before entering the exaust in the lower unit.Would that help the motor breath a little better?

[clough]

[QUOTE=The tube seems really restrictive and there is all kinds off room in the midsection to make the tube bigger before entering the exaust in the lower unit.Would that help the motor breath a little better?[/QUOTE]

Alot of guys drill through the lower unit into the restricted pipe your talking about to make the motor breath better ....

[clough]

Also forgot to add .. Done alot of research on this myself as i have the same motor but in the midsection there is a exhaust tuner for backpressure and from wht ive read on these motors dont screw with them it will only make everything else harder like tuning foreign to the motor carbs...

[Arkansas river rat]

I went into my carb collection and find the KC14A is 1-1/16". I only have one.

I found a pair of 1-3/16" carbs in the pile.

David

You wouldn't know what motor that would have came out on would you? I've also read about fractured rods . I have a 1976 50hp . would it have the fracture rods? I've read there a little better than the earlier syle of rods. Should i balance the motor ? I know it will last longer, spin tighter and hold together longer if its like a car motor. I'm also always makin a motor give me it all she has and I want it to stay together. lol for a little while.
I'm getting ready to build my first outboard motor and need all the help i can. Spring will be here soon and i can't wait! I love the sound of a screaming 2 stroke.

[formeone]

1 3/16 wont work too big,,, need 1 1/16th,,, dont worry about balancing,,, merc already bin there,, factory balace good,,,, can weight rods ,, just make sure same style .... we rev the 50 hp 8000,,no worries,,, biggest thing is to torque rods to specs and get honed so as to make them round,, in my experiance about 1 and a half thous,,,rudes about 3 thous...,, match the bigger carb to front case,,,, port motor a little and time at .215 before tdc...,, boysen reeds and 100hp merc reed stops...,,,have set many records doing just that,,, and of course porting the motor to what ya need...

[Arkansas river rat]

I still am think about building the 44 merc but i came up with another idea. I found a 70hp merc that has low compression on one cylinder. I'm think about buying it and building it first and mounting it to the 50 mid section. I found out the 1 1\16 carbs do come off 65mercs to.

[mercmack]

the 70 merc if its a 49 cu in one will fit the 40/45/50 tower housing, You just need the adapter thats below the powerhead is all..
the best machinest around the does the merc blocks is James Ruck, he is in Oshkosh, Wi phone/fax 920-233-3833...He done two of my blocks and they where a awsome work..
good luck with your prodjects :):):)

[clough]

I still am think about building the 44 merc but i came up with another idea. I found a 70hp merc that has low compression on one cylinder. I'm think about buying it and building it first and mounting it to the 50 mid section. I found out the 1 1\16 carbs do come off 65mercs to.

Guessin your talkin about the old 65s? Like not the 3cyls? Cause i believe the 3cyl are the same as the 70s 3cyl from that era?

[Arkansas river rat]

I can't remember what year models but i think they came off of a 3cylinder.I'd have to take another look at the information. Think they were in the late 70's 78 or 79 can't remember. Get to late model and the bolt pattern on the carbs are cross staggered

[Arkansas river rat]

the 70 merc if its a 49 cu in one will fit the 40/45/50 tower housing, You just need the adapter thats below the powerhead is all..
the best machinest around the does the merc blocks is James Ruck, he is in Oshkosh, Wi phone/fax 920-233-3833...He done two of my blocks and they where a awsome work..
good luck with your prodjects :):):)

Thanks I've had a few people say it wouldn't fit. I told them everything is the same except the adaptor plate which is different from the 35 to the 70.
Is the 49cu merc and pretty reliable motor? I plan on running it with a jet pump on a 1648 jon. that weighs around 350lbs but i'll lose 1/3 of the power running a jet but 49 or 50 should really push the boat.

[Fastjeff57]

You're talkin' my language! Unlike most Mercophiles out there, I actually LIKE the triples and run one on my little boat. And they are a VERY lightweight package if mounted on a Mark 55 type tower--about 145 lbs. Finally, it is an easy swap to do (once you know how) that does not require a machine shop, just simple tools.

On the triple's propensity to torch its top cylinder--and all 5 triples I've messed with had a bad top cylinder--here's the deal: The water pump used on these motors is too damn small! (The Mark 35A up to the thru-hub triple use the SAME impeller.) Compounding that insanity is that they send part of the desperately needed water flow through the fuel pump! Doh and double doh! I channel ALL of that water to the power head, where it's needed. Finally, the top carb jets need to be at least 2 steps richer than the lower one (which is what Merc did eventually).

Finally, the 65 and 70 hp (60 after the re-rating) triples are much different. The 70 has exhaust ports nearly a quarter inch higher and looses that crappy, unreliable distributor system, so go with that one.

Jeff

Here's a video on mine inaction, mounted on a 9 footer (with a terrible hull!)

http://www.youtube.com/watch?v=1oCSXMSWUEU

[Arkansas river rat]

Your little boat really hauls. I didn't know later model motors would bolt to those midsection.I have alot to learn still. I just recently got into boat motors. I wished i could get my motor that light. Lighter is always better in river running. What do you do to direct all the water to the motor. Is it just a hose you plug or is there a port you have to plug.

[Aeroliner]

http://www.boatracingfacts.com/forums/showthread.php?t=6393

This thread covers a number of the modifications. Porting is the simplest but then you can go from there.

Alan

[Fastjeff57]

To put all the water through the power head, just plug where it comes out of the power head adapter on the right side.

Jeff

PS: I even make my own sheet metal base and f-glass cowlings, anything to save weight!

[Aeroliner]

Cowl is very nice. A lot of work goes into making somthing of high quality.
Alan

[Fastjeff57]

Thanks! I kinda HATE those decals, however. Might remove them and try again.

Jeff

[Lil' Blue Rude]

If you port the motor don't use a port map from a prop motor. A jet pump motor needs more torque then a prop motor so the port maps from prop motor don't produce the torque needed. Iv'e always heard people say a prop motor is like a sprint car and a jet motor is like a pulling truck. Most jets turn less then 6000rpms so you need your peak power to be below that.

[clough]

I can't remember what year models but i think they came off of a 3cylinder.I'd have to take another look at the information. Think they were in the late 70's 78 or 79 can't remember. Get to late model and the bolt pattern on the carbs are cross staggered

i dunno man i was looking at some 3cyl 65hp carbs and they seem to be 'stuck together' with a plate not seperate check the pic attached....someone shed some light please and weather 65hp carbs that came on the 65hp 4cyl would do any good on a 44ci merc!? sounds like an easy enough 'hop-up' if you can? info please!

got the pics from : http://www.vintageoutboardparts.com/shop/index.php?main_page=product_info&cPath=9&products_id=891

[clough]

These seem to have the same bolt pattern from a 44ci merc but they ar 70hp carbs i dunno anyone?would they fit?

Same site: http://www.vintageoutboardparts.com/shop/index.php?main_page=product_info&cPath=9&products_id=314

[Fastjeff57]

Yup. Standard carbs for a 65 hp triple. The same carbs are used on the 4 cylinder 65 hp, but with different jets in the top carb and without that choke plate. The 70 hp triple used different carbs that are easy to work with and attach via long thru bolts.

Jeff

[clough]

Yup. Standard carbs for a 65 hp triple. The same carbs are used on the 4 cylinder 65 hp, but with different jets in the top carb and without that choke plate. The 70 hp triple used different carbs that are easy to work with and attach via long thru bolts.

Jeff

so the 65hp triple carbs will bolt right up to a 44ci merc minus the choke plate or the 4cyl ones:confused: sorry for stealin the tread:rolleyes:

[Fastjeff57]

No! The bolt pattern is different--wider. They bolt right up to the 65 hp four cylinder motors, however. I made some adapters to bolt them up to a 44 cuber once, but never ran it. The hole in the crankcase also needed enlarging.

Jeff

[clough]

No! The bolt pattern is different--wider. They bolt right up to the 65 hp four cylinder motors, however. I made some adapters to bolt them up to a 44 cuber once, but never ran it. The hole in the crankcase also needed enlarging.

Jeff

Well sorry for the confusion but how do you think it would run (a 44ci) good with the 65hp carbs?

[Mark75H]

Judging by the results that racers generally get with the carbs from 65's ... it will run exactly the same as it did with original carbs

[mercguy]

so the 65hp triple carbs will bolt right up to a 44ci merc minus the choke plate or the 4cyl ones:confused: sorry for stealin the tread:rolleyes:

if you want "bolt on" carbs......the KC carbs from the late 60's 65hp 4cyl will bolt on your 44 Merc, not the WM's from the 65hp 3cyl motor........

as to putting the bigger carbs on a JET motor...........I would not do it..............you will sacrifice bottom end torque...............a PROP motor will take the bigger carbs better, with the correct MODS..........

[mercmack]

the best carbs for a merc 44 is a set of a merc 800 the 6 cyl merc 800 that was 76 cu in..some time around 1961/62... first they will bolt right up ..the 800 had the same stroke as the 44 and 66 cu in merc but a 3/16 bigger bore..but if you whatch E-bay long enough therre will be some sooner or later..:):):)
then carbs to look for are KA 10,KA11 or KA14

[clough]

the best carbs for a merc 44 is a set of a merc 800 the 6 cyl merc 800 that was 76 cu in..some time around 1961/62... first they will bolt right up ..the 800 had the same stroke as the 44 and 66 cu in merc but a 3/16 bigger bore..but if you whatch E-bay long enough therre will be some sooner or later..:):):)
then carbs to look for are KA 10,KA11 or KA14

so when you refer to the KA10, KA11 or KA14 would that be the carbs i should look for as in there model...?

[clough]

nevermind answered my own question would KA16s work? there off a 6cyl 850?

[Mark75H]

Pretty sure all KA flanges are the same except for the 7's which have elongated slots.

I think they will bolt up regardless of whether they come off of a 44, 66 or 76.