compression not good?

asdasc

Senior Chief Petty Officer
Joined
Aug 28, 2008
Messages
680
Re: compression not good?

Like I tell my kids, if you have to ask, the answer is probably not going to be what you are looking for...

From what I understand, those readings are a problem. Oddly, though, typically I would have thought that if it were toast it would be an even bigger difference.

If you are turning it slowly to get the readings, try spraying a little lubricant such as Marvels Mystery Oil or better yet some Deep Creep in there and try it again. It prevents the leakdown and will give you more consistant reading to what the motor will see when running.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: compression not good?

not necessarily, did you remove both plugs, use screw in tester, and pull rope 5-6 times on each cylinder? if so i would try it with another tester, as they all read differently. if you get the same readings. if the motor will start, it would do a decarb on it. probably has never been done, and rings can stick due to carbon build up. decarbing has been known to free up rings, and raise conpression, and should be done every 2 years, more often it you do a lot of slow speed trolling.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

afterwards compression.recheck
 

freddyray21

Commander
Joined
Jun 10, 2006
Messages
2,460
Re: compression not good?

the 6 horses I think were low compression anyway. Tashasdaddy gave you good advice.
 
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