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Boring out a powerhead 1997 Evinrude 90hp

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shiman

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" Does anybody have any advice

" Does anybody have any advice as to how much you can bore out a 1997 Evinrude 90hp powerhead?

Mine has some pretty deep grooves in one cylinder, roughly .025" deep (maybe deeper).

One piston lost its ring(s), and screwed up the "head" (piece that holds the spark plugs) as well.

I am trying to determine if it is worth salvaging.

If you haven't already guessed, I am a weekend mechanic, don't yet have a repair manual, and am trying to determine if this is something I can tear into myself. There aren't too many tasks that I won't tackle (I built most of my own house, even though I had very little carpentry experience, so this didn't seem too tough. But now, I am not so sure. I don't even know the proper terminology.)

Help??? "
 
Shiman..... The usual oversiz

Shiman..... The usual oversize boring is .030 . I believe Wiseco piston go to .040 but that's cutting the sleeves pretty close.

Joe (30+ Years With OMC)
 
"roughly 0.025" . Opt

"roughly 0.025" . Option #1 bore out the block to see if it will clean up. #2 find a used block bore all cylinders if needed and you will be good to go.
 
Sparky.... There are no .025

Sparky.... There are no .025 O/S pistons or rings available for that engine.

Joe (30+ Years With OMC)
 
the man says he has a score 0

the man says he has a score 0.025" deep ! This is his guess. If this is true he would need a 0.050" piston.Wiseco pistons are available in sizes bigger than OMC original.
 
"Shiman,

I think the engine

"Shiman,

I think the engine is worth saving, and you can do the job yourself. I would advise you to have it resleeved and use standard pistons. This takes the quess work out of the picture.

I have never used Wiseco pistons ( or any aftermarket pistons ), but friends of mine told me not to even consider it.

"
 
" Is it safe to resleeve a 2 c

" Is it safe to resleeve a 2 cycle, with the ports in the cylinder wall vs. in the head like a 4 cycle?

Also, the other piston in the bank with the bad cylinder was kind of loose (sloppy). I would assume that while this is all apart it would be wise to hone the other cylinders, and put new rings on the 3 good pistons. Yes? "
 
" Shiman,

I have had quite

" Shiman,

I have had quite a few 2 cycle engines resleeved, and have never had a problem.

You should do a thorough job while you have it apart. The sloppy cylinder probably could use a boring for an oversized piston.

Tony "
 
What kind of ballpark cost am

What kind of ballpark cost am I looking at for a single replacement piston and rings? Or for 4 oversize pistions? For having 1 cylinder resleeved and the rest honed?

Boring vs. honing?

Where is a good place to have a powerhead resleeved?

I just have no idea what kind of costs I am looking at.
 
" I just found out (determ

" I just found out (determined) that this motor is a 1992, not a 1997. The guy I bought it from (3 years ago) told me it was a '97, and I saw nothing, nor had any reason, that would make me suspicious about the age of the motor. Yeah, I know, I should have had it inspected by a real mechanic, but I didn't.

Does anybody still think it is worth fixing a motor of this age considering the amount (cost) of work that needs to be put into it?

One cylinder is badly scarred/grooved, another is slightly scarred, and the other two look great. A minimum of one new piston is required, and the head either needs to be cleaned up or replaced.

Besides new rings all around, what else should be replaced while it is completely torn apart? "
 
Just bored a 115 1978 and put

Just bored a 115 1978 and put 4 new .030 pistons and did it myself and I have appox. (with powerhead gasket set...) 450.00 in it. Doing ALL the work myself. NAPA is a great place for replacement pistons gaskets etc.Just food for thought. A 90 HP will be pretty close to the same price.
 
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