Yet another powerhead swap question

[fsds123]

I have a 1979 Evinrude v4 115 with a bad powerhead. I have found a 1981 90 hp evinrude powerhead someone is selling cheap. He knows nothing about it. Are there any 1981 90hp evinrude powerheads that do not fit? It's a pretty far drive so I figured I'd ask here first. I'm trying to see if he can get a model number. Are all 1981 90 hp evinrudes crossflow, and thus it should fit? Direct bolt on?

 

[Dhadley]

Re: Yet another powerhead swap question

As for bolting on it's a direct fit, no big deal. Just be sure to use the 90 carbs. Everything else is a direct swap. Even the carbs will work it'll just use more fuel without any benifit.

 

[fsds123]

Re: Yet another powerhead swap question

So are the pistons smaller on the 90hp? I thought the block/pistons were the same for 90, 115, and 140 hp v4's, and different carbs and or exhaust and such made the difference in hp. So bolting on this powerhead and carbs would give me a 90hp, not a 115?

 

[Dhadley]

Re: Yet another powerhead swap question

In the years you're talking about the pistons, rods and crank are the same. The port timing is different. If you bolt on a 90, you'll have a 90 regardless of what carbs you use. In fact the big carbs on the 90 porting will probably rob some power.

 

[fsds123]

Re: Yet another powerhead swap question

Ah, good to know. Thanks!