OMC 120 low on one

[Gus Mortimer]

I was trying to fix a rough idle when I discovered a 60# reading on one cylinder, 130# in the rest. <br /> I feel I should mention that the boat is running the same as it was last year, I just felt like trying to get it perfect. at high RPM it seems fine and even at 1700 or so it seems fine.<br /> Any thougts?

 

[Walt T]

Re: OMC 120 low on one

Hey if you think it does okay, keep running it. Try a running compression test. Remove the spark plug in the low cylinder, install the gauge. Fire it up see what it reads. Bet it builds up okay. You can also try a wet test, squirt some oil in there, do another compression test. If it comes up then its probably rings. If it doesnt maybe you can get away with a valve job.

 

[Gus Mortimer]

Re: OMC 120 low on one

I did a compression test and i got a 60# reading on that one cilinder, if I rev it up I can get 90 but thats it, I did a wet test and it was exactly the same. <br /> Is it posable if my valves "look" good to just clean them off well<br /> I have heard of a paste or something that you can use to re-seat?<br /> It is an old boat and I allready have too much money in it.

 

[Bondo]

Re: OMC 120 low on one

Why would you go through All the work of Pulling the Head,<br />And not send it to the MachineShop for a Rebuild ???????<br />Lapping the Valves would be 1/2a$$ed at Best.....

 

[Walt T]

Re: OMC 120 low on one

If you can put up with it, leave it be. Go have some fun and worry about it next winter. Maybe Santa will dump 5 pounds O money on ya.

 

[Gus Mortimer]

Re: OMC 120 low on one

Yea I guess you are right Bondo, about having it done right and all, just getting tired of dumping money. <br /> Will I be doing any harm to the motor by not fixing it now? I really would like to enjoy it now.<br /> I think it was like this all last year and I didnt know. Its just now that I know...<br /> This of course comes at the end of about eight straight days of putting in a new interior, new manifold/riser, rebuilt carb and various other little things, so you can probably see why I am not wanting to undo all that I have done.<br /> If and when I do remove the head for servicing, how much can I expect to pay?