15'2 Coastal

[Coastal]

Just finished rebuilding my 1994 15'2" Coastal. I put a new floor in it, fixxed every nick and inperfection on the bottom, painted insided and out w/parker duck boat paint. Upgraded from a Mercury 40, to a Mercury 60, fresh rebuild, 30 over, w/16p Vengence Prop. With the Merc 40 that was on the boat I could get right at 39 mph. I was expecting much better numbers with the 2 stroke 60. I gps'd the boat the other day and got 42-43 mph. Help, any ideas to get a few more mph.. I weigh about 280, the boat will not lift as it is, I do have the battery in the front thinking about mounting it in the back.

- Cleaver/Chopper?
- Jackplate, 4 or 6 inch setback

[88workcar]

For starters move the batt to the back, and use a little battery, garden tractor battery is best. The from the looks of the pictures your motor is way too low. The less setback the better. See if you can lift it with no setback. As you lift you will need more prop.

[Jackson]

Good looking Boat :)

[Coastal]

Jackson, thanks. 88, the transom has actually been built up. It was much lower. The cavitation plate actually is maybe 1 inch above the bottom of the pad. Thanks for the input, I have always thought that a setback would help, your saying try not too. Thanks.

[milkdud]

Looks like your adding close to 5 mph to that rig by going up 20 hp.

On the same boat and set up it takes big HP increases to get lots of MPH in the upper range.

Friction adds up hard on the top end. Im not sure about your motors but Mercury and other manufacturers for that matter sometimes use the same cubic inch block for several hp motors. So going from a 40hp motor to a 60 can be a less than satisfying move.

Playing with set up and props will help.

Nice boat!

Conrad

[milkdud]

Just as I thought.

http://www.defender.com/inflatables/outboard_project/mercury/mercury_2/merc_75.html


The 40, 50, and 60 hp 3 cyl 2 strokes are ALL 966 cc motors.


So I say your doing well for what you have.

To put it into perspective the 75hp OPTI has 1526 cc. Rated only 15 more HP than your motor but has more that 50% MORE CUBES. And more weight :)

Now that 75 opti is gonna produce good hp with that much displacement. Kinda a sleeper. Yours is probably using all the tricks in the book to be putting out 60 hp.

Conrad

[mad yama]

I have the same boat with a 40 yamaha that run 60 62 allday long need to take as much as u can out the ft and i have light boat

[milkdud]

I have the same boat with a 40 yamaha that run 60 62 allday long need to take as much as u can out the ft and i have light boat

That sounds amazingly fast. Are you using a GPS or what for these readings?

Ive been amazed before at how fast some boats can go, but 62 mph out of this style boat and only 40 hp seems a bit faster than reality.

Conrad

[Coastal]

My lil brother has a 15' Fast Craft w/60 Merc, runs in the low 50's. It's a light boat. I've got a heavy new floor.

[milkdud]

My lil brother

Costal, If your little brother is lighter than you and his boat is lighter to boot then I could easily see more speed out of his boat.

It sounds like you got your motor up where it should be, but I'm guessing your total weight is higher then your brothers.

Good luck and nice boat
Conrad

[Coastal]

Yes, I'm sure my boat is much heavier than my bro's just posting in relation to the 40 hp, 60-62 mph post. R/Chip

[Coastal]

43 is still pretty fast in my opinion sitting so close to the water, maybe seems faster :-), just when I hit those long straight aways, I'd like her to lift. Might just have to settle for now as I fish more than just ride. It's a good compromise. R/Chip

[milkdud]

You are very correct. 43 MPH will feel very fast on water. I have a 150hp pushing a 14 foot boat 70 mph. My friends that dont boat think that its no big deal since they can drive their Civic 80mph on the freeway while eating a cheeseburger and talking on the phone.

On the water low to the water line things "feel" very very fast. Thats why its fun :)

Ive taken my friends out and gotten them just above 60 in my little boat and they start yelling slow down :) And most of them thought we were going 90 mph :)

In my opinion your doing well with your set up. Of course every set up including mine can be tweeked just a bit more to get more performance.

Conrad


43 is still pretty fast in my opinion sitting so close to the water, maybe seems faster :-), just when I hit those long straight aways, I'd like her to lift. Might just have to settle for now as I fish more than just ride. It's a good compromise. R/Chip

[mad yama]

43mph is stock speed for a 40hp motor if your setup is right remember my motor is not stock and the boat is the light boat ever build it is setup and prop

[milkdud]

43mph is stock speed for a 40hp motor if your setup is right remember my motor is not stock and the boat is the light boat ever build it is setup and prop

Post a pic of your boat. I find your 60 mph boat interesting.
Conrad

[seapro]

Just as I thought.

http://www.defender.com/inflatables/outboard_project/mercury/mercury_2/merc_75.html


The 40, 50, and 60 hp 3 cyl 2 strokes are ALL 966 cc motors.


So I say your doing well for what you have.

To put it into perspective the 75hp OPTI has 1526 cc. Rated only 15 more HP than your motor but has more that 50% MORE CUBES. And more weight :)

Now that 75 opti is gonna produce good hp with that much displacement. Kinda a sleeper. Yours is probably using all the tricks in the book to be putting out 60 hp.

Conrad

that lil block can make way more then 60 hp :cool:

[milkdud]

that lil block can make way more then 60 hp


Sure Im sure most every motor can be modded to make more hp, but that is not really the point here.

The man is trying to set his boat up with "what he has" I believe. Adding another layer of irrelevance is irrelevant.

Ill check this in the morning and see if it makes sense :)

Conrad

[milkdud]

The 75 opti was just for reference to how much the cubic displacement changes in that motor series to make its HP. ONLY GIVEN AS A SIZE REFERENCE.

That reference mainly pointed to how the 40-50 and 60 hp motors are all the same 966 cc motor. And going from a 40 hp version of this to a 60 hp version of the same block is not going to be as much of a gain as one may think.

I never said to mount a 75 opti on this boat. It was a reference point made. And I may have over stated my"every trick in the book" statement. I ment it more as a general "its the top of the line for that block series"

This is not a performance boat. Its a general working boat, so how much gain are we going to see on this rig by "tricking out the motor"??? Id say much less than its worth.

The biggest bang for the buck will be proper prop selection engine height and weight management.

Unless he mounts this 60 hp on a 200 lb hydro, working on port maps, assembly balance, NOS, lightened flywheels, tuned pipes, shaved heads and other race adventures are really not applicable unless he has nothing else to do and wants to spend lots of time and some money for little gain.

Bottom line is your right, the motor can be made to produce more than 60 hp. Thats true for most any stock motor. But how many people want to do that to their 60 hp tiller on a fishing boat?

[JohnsonM50]

In the end its up to Coastal if he wants to go to the expense of upgrade, If the boats run weight is heavy that remains a strain on 'potential' It as is could probably be a little better w/o major cost or downtime, 43 ain't bad at all considering. Generally more hp = a little more speed & alot more acceleration. To get the speed it needs the work & several props to be tested. Good Luck :cool:

[88workcar]

Well I'm not going to try and convince you anything but I've made a good living for 6 years biulding this exact block at hand! You can take a pic of any bolt on that motor and I can tell you were it goes. This motor can push a load and gaid 1000 rpms on top end no problumb at all. Were we come from if you find an unmolested tiller 40 it's out of the norm. I have no idea how this even got started if we were talking about anything but this motor I mind my own biz and let you speculat and relate till your fingers fall off everyone has there thing and this is mine I know what they can do and how to make them do it. We have been invited to a race in bogalosa la coming up if you want to see some inovation come put your rigg in the water and race some of these 3 cyl 59 ci motors

I will agree with you seapro. I just had the same stuff going on. I know what I can do with certain Yamaha engines and got questioned ridiculed and fussed at about it. I did get out of hand a little because the guy said that what I said was BS. But I have decided (again) to never argue here again, I'll say my piece they can take it or leave it...... Yes yall motors are awesome. 8800 with stock parts is talking the talk. I can do it with a 40 too but yet to get the 90 into that range. I have a johnnyrude on the bench right now, lighter than a 90 Yammi hint hint hint......

[milkdud]

SEAPRO,

I dont think I have ever doubted that you can turn this motor into more than it is in factory form. You win, wow ,but how do you win when I agree....? you dont listen to what I write.

My point is do you think its worth it with his set up?? Let me know your thoughts on that?? Is it worth tearing down the motor to do this??

Or would he be better served with motor height or a prop change that takes ONE nut to take off and put back on.
I run a 1500xs on a semi tunnel. I can get OVER 10 mph speed change depending on what prop I put on the boat. Weight and height offer more gain as well depending where your at.

You can alter ports smooth runners put in reeds but if your 3 blade aluminum fishing prop is buried with the cave plate dragg'n then you'd be better served doing the easy stuff first.

I dont think this thread was looking for full tear down mods to get more speed. If the man comes on here and says he is looking to pull his motor down and start altering things then Ill be damned :)

Have a nice night.

[88workcar]

Uh sorry milk dud, I missed that too LOL. No for you, I would work on set up. Props and motor hights. That old motor has been modded many times over the years but they had good gas and no other options. That is a big task to mod an inline, and the racing parts are rare.

[milkdud]

88workcar,

Again I am still only talking about his set up not mine. My set up was just another reference to what prop changes can do for top end speed. And how props can be one of the biggest parts of the puzzle.

But you are very correct the inline 1500xs does not have much left to mod at all. Only thing I did was balance the rotating assembly when I rebuilt it.

Thanks
Conrad

[milkdud]

Thats pretty fantastic your getting 100 hp out of that motor. Sounds fun. How's the idle on a beast like that? I was expecting close to 80 hp but 100 is pretty amazing.

Ive always wondered how people come up with HP numbers after they have modded a motor? Is it mostly approximations or do a lot of people have access to dynos?

Your probably not going to get a lot of people wanting to spend $2000 dollars to do this. More than likely they have a budget for a good used stainless prop in the $200 mark. Just reality for 8 out of 10 of us.


Post me a photo of your 62 mph rig sometime. Sounds like fun
Conrad

[88workcar]

Getting back to coastals question. I had a stock 40 on a aluminum boat (skiff) I did all the set up that I could and still use the boat as a ride around. My best ever speed was 39mph. For around here it was fast for a 40. I then got the 90. First day out I ran 42, I can't tell you how dissapointed I was. In the end, I ran 58 with that 90. Same 90 I switched to the Allison and was awarded with 62mph. Again went to setup and got 70.5mph.

I know that coastal is a good boat, Set up is normally worth more than anything. And For motors, you do have one that accepts mods very well.

[Smokin' Joe]

Just finished rebuilding my 1994 15'2" Coastal. I put a new floor in it, fixxed every nick and inperfection on the bottom, painted insided and out w/parker duck boat paint. Upgraded from a Mercury 40, to a Mercury 60, fresh rebuild, 30 over, w/16p Vengence Prop. With the Merc 40 that was on the boat I could get right at 39 mph. I was expecting much better numbers with the 2 stroke 60. I gps'd the boat the other day and got 42-43 mph. Help, any ideas to get a few more mph.. I weigh about 280, the boat will not lift as it is, I do have the battery in the front thinking about mounting it in the back.

- Cleaver/Chopper?
- Jackplate, 4 or 6 inch setback

How high's the transom, long or short shaft motor? 40 to 60 hp increase gives
expected speed gain of 20% if you ignore the weight difference of the motors so it sounds like the 60's not up to par. Or: you have a hook so bad that you're on;y driving the bow into the water with more power. Get a straightedge and sight down the pad and running surfaces adjacent to the pad, should see no daylight. Tap on the bottom with metal like pocketknife end and listen for hollow sound (glass separated from wood). .

[Smokin' Joe]

Just finished rebuilding my 1994 15'2" Coastal. I put a new floor in it, fixxed every nick and inperfection on the bottom, painted insided and out w/parker duck boat paint. Upgraded from a Mercury 40, to a Mercury 60, fresh rebuild, 30 over, w/16p Vengence Prop. With the Merc 40 that was on the boat I could get right at 39 mph. I was expecting much better numbers with the 2 stroke 60. I gps'd the boat the other day and got 42-43 mph. Help, any ideas to get a few more mph.. I weigh about 280, the boat will not lift as it is, I do have the battery in the front thinking about mounting it in the back.

- Cleaver/Chopper?
- Jackplate, 4 or 6 inch setback

Here's a 1980 boat with a firm bottom set up and propped right. Boat's about 350lb, I'm 185lb. 1983 Johnson 35. With stock Stiletto 10x14 (actually 13" pitch if you measure it) or with an al OMC 10x13, 37 mph. With the prop just right, and it's tricky, 2 way avg. of 41.7 mph on GPS. The motor has too little power to get the boat completely on the pad, but with a tiller handle it still feels like it's up.

[seapro]

That is a very nice boat smokin Joe I love it

[Smokin' Joe]

That is a very nice boat smokin Joe I love it

Was made from the bottom of an experimental 14' race boat that wouldn't turn. Good fishing boat, can walk from side to side without kipping due to the flat chines. And turns as flat as a pancake too!

[88workcar]

That is a very nice boat smokin Joe I love it

MY EXACT THOUGHTS. I would love to have it with a 40 on it, good GOD can you emagine the expressions when you come around someone, Damm let me have it Joe, please please please....

[seapro]

smokin joe can you start a thread of you ow so we can ask questions about this little boat

[Smokin' Joe]

MY EXACT THOUGHTS. I would love to have it with a 40 on it, good GOD can you emagine the expressions when you come around someone, Damm let me have it Joe, please please please....

The hot motor would be hard to find. The ca 1995 3 cyl. OMC 35 looper designed by Jim Nerstrom. The motors nearly are nonexistent, would need shortshaft with tiller. He told me it's more like 40-45hp.

I first saw the boat outside i a Mercury dealer's lot ca. 1980 in E. Ky.. I thought, let it sit a few years then offer something. In 1982 it was still there, he wanted $1000 with trailer. The boat retailed for $2000 then. Louis Collins and I both had the XR-14 in 1978, Darris' first attempt at a raceboat. I set the EP record with mine in 1980, traded it back in 1982 for a std. 13'. Louis traded his back for a 20' in 1978. Louis' XR-14 was sawed up, bondoed, etc, and became the EP-15, which is what my fishing boat is called. There were about 20 made, maybe 4-5 survive. Mine was kept dry so the wood between the glass layers didn't get wet and rot.

[milkdud]

I really like that boat!
Conrad

[Coastal]

Couple pics from early fall, me and two brothers playing on the Waccammaw. One is of my bro Jay and his Fast Craft. Good times. Love my Coastal just wish it were bigger.