Yamaha compression check

[ScoReb]

Hi all,<br /> I'm looking at purchasing a used boat which is fitted with a 1996 Yamaha 150. I want to do a compression check on it but Im not that familiar with 2 strokes. Can anyone tell me what pressures to look for and maximum variances between cylinders?

 

[corm]

Re: Yamaha compression check

Hi ScoReb,<br />The cyl 1 & 2 should be the highest and 5 & 6 will read the lowest. Max difference is 15#<br />this means trouble. Personally I think 6-10# is alot. Sorry I can't find the spec no.for the comp, but hope this helps some.<br /><br />corm

 

[ScoReb]

Re: Yamaha compression check

Thanks for the reply Corm, I'll be doin' the check late this afternoon. Strange that it is normal for certain cylinders to be higher/lower than others, but thats why I'm lookin' for advice here because I know little to nothing about outboards

<br />At least now if I find the numbers to be the way you say they may be, I'll feel better about it. btw, comp. test by his marine mechanic says he measured 130# across all 6, I'll find out for sure later today.

 

[corm]

Re: Yamaha compression check

Hi SoReb,<br />Hope theyare even like he said . That wwould be great.<br /><br />corm