85HP Outboard on 15" Boat

I am looking to upgrade my 35HP Evinrude outboard with this:<br /><br /> http://newyork.craigslist.org/lgi/boa/116477058.html <br /><br />My boat is 15" and rated up to 85HP. My question is if this is too much power even though the boat is rated for this HP. Would there be stability problems? (It's a tri-hull)<br /><br />I also am concerned as to whether this will weigh my boat down too much. If I stand on the transom while my boat is in the water, the stern does not sink very much into the water. The current outboard (120 pounds) plus myself (140 pounds) is almost equal to the roughly 270 pound 85HP V4. <br /><br /><br />I'll update with the model number as soon as it's given to me.

Re: 85HP Outboard on 15" Boat

Oh, thank God!!<br /><br />I thought you wanted to put 85hp on a boat with a 15" transom! <br /><br />It is rated for 85hp. You should have no problems.

Re: 85HP Outboard on 15" Boat

You better make darn sure your transom is PERFECT. Give it a thorough check for rot. A big engine on a weak transom will have an obvious end result.

Re: 85HP Outboard on 15" Boat

I have a Skeeter SS-1 Fisherman, also 15 feet, and I have a 4 cylinder 75 horse mercury on it. It is also rated for 85 horses, my boat performs fine and there are no trim or stability problems, pretty fast though As long as your transom is solid and the hull is in genrerally sound condition you should be fine. Good Luck!

Re: 85HP Outboard on 15" Boat

Thanks for the thoughts guys<br /><br />How can you check your transom for sturdiness? Also, another thing - This motor has no electric trim & tilt. I'm reasonably strong, but is it a real hassle to manually raise an engine of this size?

Re: 85HP Outboard on 15" Boat

Skip it and find one with T&T. <br /><br />Proper trim, which varies with different loads and load distribution, is critical to efficiency and performance. The bigger the engine the more critical it is.

Re: 85HP Outboard on 15" Boat

I have a 15 1/2' tri hull Glastron with an 85hp Johnson V4. great combo. I don't have trim, but I did convery my manual tilt to electric "tilt only". WIsh I had trim, but It's not too critical for this boat. She will run near 40 as is.<br /><br />The manual trim models have a cylinder to help lift the motor. I have a bad back and it wasn't too bad, but that's why I tracked down an electric trim.

Re: 85HP Outboard on 15" Boat

Just curious Jason, how much does your boat weight? Mine's 890 lbs. Also, how much did it cost you to convert it to electric tilt? I see units going for $500+.

Re: 85HP Outboard on 15" Boat

Is the cowl of that motor the original???<br /><br />Looks like a 1971 to me. The decals do at least. The colors are way off.

Re: 85HP Outboard on 15" Boat

I wouldn't worry too much about the weight of the motor. If the boat is rated for 85HP I'd bet the motor weight will be just fine.<br /><br />With the gas cylinder on the motor, and a properly adjusted hinge pin you shouldn't have too much trouble raising or lowering it by hand.<br /><br />The weight you SHOULD worry about is the gas cans you need to carry down to the dock twice a day to feed that monster. A mid 70's 85HP OMC will gobble up gas PDQ!

Re: 85HP Outboard on 15" Boat

Originally posted by JB:<br /> Oh, thank God!!<br /><br />I thought you wanted to put 85hp on a boat with a 15" transom! <br /><br />It is rated for 85hp. You should have no problems.

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Why the eek JB? My last boat (below) was 16',had a 15" transom and was rated to 85hp...? I'm confused.<br /><br />

Re: 85HP Outboard on 15" Boat

Still considering the 85HP, but still shopping around. A 60-70HP outboard would be most ideal.<br /><br />How are these motors?<br /><br /> http://newyork.craigslist.org/lgi/boa/117154909.html <br /><br />It's cheap...but there's a hidden cost. I'd still have to get new controls, etc.

Re: 85HP Outboard on 15" Boat

Mk, my boat is "listed" at 840 or 860lbs. I gutted mine and rebuilt it though, so it could be 100lbs either way. I paid $15 for my unit used, but they are a bit rare. Couldn't spring for the CMC PT-130, but would love to have one. Trim units have to be from '74-'77 V4's. The more common '78 and up won't fit. The tilt only unit I have was a "dealer added" item only. In general, on the '73-'77, if it haqs one cylinder in the middle, its tilt only. Full tilt/trim has an outboard mounted cylinder on either side I believe. Judging by how much of a pain it was to install on my freshwater motor, I'd look hard at the CMC unit if you really want trim with that motor.<br /><br />My boat is rated for a 100hp. For reference, head over to classicglastron.com and look in "The Years" at a 1976 T-156. It's 15' and rated for 85hp. Mine is a '76 T-166, just a bit bigger.<br /><br />That e-rude you are looking at os a copy of my Johnson. great motor, but has a couple things to know. '74-'77 85hp OMC's are different from those before or after. Biggest difference is the hydro-mech gearcase. Works great, but not as plentiful as the later styles. Also, the '76 85hp at least has a smaller ci displacement than the other 85's over the years. Parts are still out there and pretty easy to get, but can be different from other motors. Mine still runs like a top. In the last 5 years, it's needed a powerpak (looked original) and needs a solenoid now. Not bad for a 30yr old motor. Fuel economy leaves something to be desired (1.5mpg at 80% throttle), ut she's solid, reliable, and cheap.

Re: 85HP Outboard on 15" Boat

JasonB ... out of curiousity, how fast are you going when you are at 80% throttle?

Re: 85HP Outboard on 15" Boat

32-34-ish depending on if I have a passenger or not.

Re: 85HP Outboard on 15" Boat

Jason thanks a lot for the info!<br /><br />I'm not too sure about getting an 85HP now just because of the fuel economy. I honestly can't afford to fill up after every one or two trips. Maybe I'm just used to my dad's four stroke and my 35HP outboard. <br /><br />Would a 3-cyl 60HP outboard offer a significant improvement in fuel economy?

Re: 85HP Outboard on 15" Boat

Originally posted by .Pony.:<br /> Is the cowl of that motor the original???<br /><br />Looks like a 1971 to me. The decals do at least. The colors are way off.

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The pan under the cowl is post 1972, it was changed for 73 to allow for a cable for the gearshift. the pre 73 didn't

Re: 85HP Outboard on 15" Boat

MK, the fuel economy is managable. If you back down to say 2/3 throttle, it gets much better. When we used the boat as a ski boat, we could run for hours on 12gal. I would carry 2 6gal tanks and a 3gal. The 3 was my reserve. I can go fishing by myself and avoid WOT runs, and I Bass fish all my favorite holes on ~3-4gal.