buying engine

[vtdave]

Hi, I need help....I am due to buy a used boat with a used engine on Friday...it is a 1998 200 h.p. (s200txrw)....I think it is a salt water II if not mistaken...the compression test was as follows: top left-down 121, 121, 98 top right down 120, 120, 114. What do you guys think of these numbers? Does this indicate a problem? Is this generally a good engine? Please, I need your help...Thanks, Dave.

[tripleb]

Hello vtdave,

I have read and been told by outboard mechanics that compression should test no greater than 10% difference between cylinders.

I would be concerned with the one cylinder that is 98lbs.

[jb123]

very concerned. suggest they shock with ring-free to see if it would loosen it up a bit.

[vtdave]

According to the seller, the mechanic "suggested a fuel additive that would easily clean carbon from the pistons, etc. thereby increasing compression." I just don't know if that sounds right. Is this a good engine normally? Thanks for any info you post(ed). I really appreciate it.

[Ken]

dave,
I would have that mechanic do a shock treatment with SeaFoam or RingFree to see if the compression will come up in the cylinder that is 20% below the others. And, yes, if the rings are stuck due to carbon buildup, then an application of a strong detergent can loosen them, and thereby bring up the compression.
If a shock treatment doesn't bring up the compression, then I would be concerned that there may be a broken ring in that cylinder .
Good luck [img]smile.gif[/img] ,
Ken K

[vtdave]

thanks for the advice everyone.