90hp V4 on an SS160?

[ShoestringMariner]

I want to re-power my 16’ super sport. I think the hull is rated for 85 horsepower, So I’m assuming that five horsepower over that is it really anything to fret over.
what I am concerned with is overall weight of this motor combined with a 9.9 kicker beside it. (not to mention the starting battery and two or three fuel) cans My transom is being rebuilt this spring. The knee brace at the Keel I believe is in good shape, no cracks. There are no cracks in the splash well either.

I was originally looking for a 70 horse Johnson/Evinrude or Yamaha but this motor came up and it looks pretty clean with good compression.

Think I should wait out a 70? I think the Evinrude Johnson’s are about 50 pounds later. Yamaha possibly lighter even?

 

[Watermann]

What is the 90? Make and year would help forming an opinion. 90 Yamaha's are 3 Cyl and pretty light whereas the V4 JohnnyRudes are heavier.

As far as the rated HP goes, a 90 should not be an issue on a rebuilt boat in my opinion.

Stacking all that back in the stern area may cause some porpoising issues for your 16'r though.

 

[ShoestringMariner]

Thanks. It’s a 1984 Johnson with PTT. About 315lbs I think

 

[bchaney]

I agree with WM, 5hp doesn't seem like a big deal, especially considering that the actual HP of the motor can vary up to 10% of what's on the cowling. BUT, consider that sometime in the 80s outboard manufacturers switched from crankshaft rated HP to prop rated HP. I'm not sure when that happened on the Johnsons but it could be that the 1984 was prop rated which means it's got more power than a 90hp motor made when your Starcraft was rated for 85hp. It's probably worth looking into.

https://forums.iboats.com/forum/eng...oards/260812-powerhead-rated-vs-prop-rated-hp

 

[ShoestringMariner]

I agree with WM, 5hp doesn't seem like a big deal, especially considering that the actual HP of the motor can vary up to 10% of what's on the cowling. BUT, consider that sometime in the 80s outboard manufacturers switched from crankshaft rated HP to prop rated HP. I'm not sure when that happened on the Johnsons but it could be that the 1984 was prop rated which means it's got more power than a 90hp motor made when your Starcraft was rated for 85hp. It's probably worth looking into.

https://forums.iboats.com/forum/eng...oards/260812-powerhead-rated-vs-prop-rated-hp

Thanks, valid point. I just had a thread about that very thing. I think someone said 1985.

 

[Watermann]

Yeah I would't let that small difference in HP get caught up my spokes, like I said with a new transom and fasteners. If someone had an original boat that was all loose and rotted then I'd have a different take on things.