Realistic Compression Readings for a 12 year old engine

[happyzee]

I have a 1991 Force 150 with one cyclender reading 110 psi, all the others are 125 or over. The engine runs smooth but seems to be having carb problems (will not reach RPM/MPH). A couple of shops have looked at it and said the engine is shot and may "blow" and refuse to work on it. <br />This engine is 12 years old. The book says no more the 10% between cyclenders (Yea, On a rebuild maybe!)<br />What is reasonable and acceptable for an older engine?<br /><br />Your experience/opinon is greatly appreciated.<br />Thanks is advance<br /><br />kz

 

[Bob_VT]

Re: Realistic Compression Readings for a 12 year old engine

That sounds right in the ball park. Your compression is okay. Allot of people and mechanics tend to shy away from force regardless of age. Based on the opinions "A couple of shops have looked at it" you have received there might be more problems. I can't honestly say to ignore all the mechanics who have checked it they are in the business. Sorry, I can't give you piece of mind on it either but, the compression is okay.<br /><br />Bob

 

[gw204]

Re: Realistic Compression Readings for a 12 year old engine

My '85 Merc. 150 blew 109 - 118 last December and this year I have been using the Quicksilver Quickleen carbon guard additive. I'm curious to see if those number have changed any.

 

[happyzee]

Re: Realistic Compression Readings for a 12 year old engine

Has anyone tried additives to help "Decarb" an engine and has it helped?<br /><br />Thanks again

 

[DJ]

Re: Realistic Compression Readings for a 12 year old engine

happyzee,<br /><br />Doing the decarb. on a Force is a must.<br /><br />That just might fix you up and it certainly won't hurt anything.

 

[JGKoenig]

Re: Realistic Compression Readings for a 12 year old engine

What size boat do you have it on, and how many RPMs are you getting. I have an 83 Chrysler, if you think mechanics don't like Force, trying getting an opinion on an old Chrysler. Sounds like your compression is good, and should clean up the carb or carbs.

 

[happyzee]

Re: Realistic Compression Readings for a 12 year old engine

The boat is a 91 18' Cobra. The reason I "know" something is amok is that after 3 hours of running at 42mph/4000rpm the engine, on another WOT, jumped up to 58mph/5500rpm. It through me a bit, so I dropped the throttle back. When I tried WOT again, all I could get was 42mph/4000rpm. By that time I was just about empty and called it a day. <br />I am going to take all your advice and first try just cleaning the carb's (Using JUNK I guess). Check the floats ( I noticed that pumping the bulb causes gas to come flowing out the lower carb. I suspect a stuck float????<br />