Rebuilding 1990 90 hp Evinrude

[GlasV162]

I'm having my 1990 Evinrude 90 hp rebuilt this coming winter. Does this motor have cylinder sleeves that can be replaced, or do the cylinders have to be re-bored and oversized pistons installed? Thanks.

 

[Solittle]

Re: Rebuilding 1990 90 hp Evinrude

Either depending on the condition of the bores and your machine shop should give you a recommendation. Most common is rebore & pistons. - - - Oh and you do not always need to do all four holes.

 

[Walker]

Re: Rebuilding 1990 90 hp Evinrude

They don't actually replace the sleeves. The sleeves are over-bored and inner sleeves are put inside the old sleeves.

 

[GlasV162]

Re: Rebuilding 1990 90 hp Evinrude

Does this mean the motor will need oversized pistons? And if so, how will this affect the performance of the motor? Thanks.

 

[Chinewalker]

Re: Rebuilding 1990 90 hp Evinrude

When compared to when the motor was new, the oversize pistons will give you "new" performance. If the motor has been getting tired for awhile, then you may notice a performance increase. The increase in actual displacement is minimal and really doesn't affect horsepower output that much, if at all... You're only adding .030" to the cylinder bore diameter.
- Scott

 

[GlasV162]

Re: Rebuilding 1990 90 hp Evinrude

Thanks........another question: should anything else be replaced when the motor is torn apart, other than rings and pistons? Also, I just found out that I can purchase a factory-rebuilt powerhead for about the same price. Would this be a better way to go than having my powerhead rebuilt locally?