90 compression oin both

[xtremefisher1]

hey i have a 63 40hp big twin and i did a comp check on both cylindersand they are at 90 on both.. now i am wandering if that could be a head gasket issue and not nessacerliy a bad set of rings..

model 40353

i dont want to get rid of this motor but need some help on what could be the cause of the low compression... and it being the same thing on both cylinders i would think its a head gasket issue..

but i shall let the evirnude/johnny gurus help me out

 

[Daviet]

Re: 90 compression oin both

Has the engine been sitting for some time, is it a pull start or electric start?
That compression is not all that bad, does the engine run?

 

[xtremefisher1]

Re: 90 compression oin both

i had redone the motor this summer ande took it out and ran it a few times.. i then checked the compression and it was at 90.. could it be a head gasket issue?
it does run pretty good but is hessitant on take off..

 

[Daviet]

Re: 90 compression oin both

I guess if you replace the head gasket, you might improve it a little.
I don't think that is the cause of a hesitation, I would look at the carb, as long as the spark is good.

 

[xtremefisher1]

Re: 90 compression oin both

it has good spark. it is electric start. also tgere is some unburnt oil coming out from a couple of tge outer head screws . and around the top plug

 

[Daviet]

Re: 90 compression oin both

With the leakage around the bolts, it might be a good idea to replace the head gasket. Make sure to check the head and make sure that it is flat. Leakage around the plug could be the compression gasket around the plug itself.