1997 120hp Force

PLease bare with me as I am a novice user on this forum page. I posted another message earlier today..(See...Compression Problems 1997 120hp Force)<br /><br />More info....After decarbing the motor my compression was greatly improved...but still not to spec........top cylinder 90psi, next cylinder 155psi,next cylinder 155psi and the fourth or the bottom cylinder 155psi......I noticed the top two cylinders had carbon buidup on the plugs after the the decard process. The bottom two cylinder plugs looked as they should.....am I making headway here with the decarb procedure?...Should I do it again?......Is there something I should look at with the top two cylinders because there was carbon on the plugs after the decarb process?.......Thanks to all of you Boat Motor Technocrats out there....Any advice you can provide is greatly appreciated........

Re: 1997 120hp Force

You could pull the head, and ckeck cylinder walls for scoring.

Re: 1997 120hp Force

Decarbing will not bring that cylinder back. Might just be a head gasket and they are around 50 bucks. If there is damage to the cylinder or the pistons you could be looking at some serious cash.

Re: 1997 120hp Force

Dont know if this helps or is even related, I have 1995 120 force and after I devarnished my top 2 were much worse than bottom! My compression.<br />Top 145<br />next 150<br />next 150<br />bottom 150

Re: 1997 120hp Force

Thanks for the input guys and or gals....Im getting ready to pull the cylinder head off..as I have a head gasket ordered to arrive tomorrow...Is there a chance that there is a cylinder inside of the head or will they all be retracted in the power head?<br /><br />Thanks in advance

Re: 1997 120hp Force

Thank you all......The good news is I have identified the problem.....Top cylinder is toast...scored to the max....The bad news is the local marine machine shop cant get it in for three weeks.....Summers are short here in NY.....I feel like running it anyway this week....cant get any worse or could it?....the damage is already done.....<br /><br />Thanks again folks...