low compression 90hp L6 Marnier

[ol''joe]

I have a '86 90hp in line 6 with 90# compression on one cylinder. The rest have 125 to 130. This motor runs well at all RPMs except idle (runs rough) and is a little hard to start. It's on a 15.5' fiberglass bass boat and will push it 50MPH. Should I have this motor worked over or run it untill it loses the cylinder completly.

 

[12Footer]

Re: low compression 90hp L6 Marnier

Try fogging it first,and re-test the compression. It may be carboned-reeds or stuck rings.At any rate, it's not healthy to run it like that. If you cannot bring-up the compression with cleaning, it should be torn-down.<br /><br /><br />------------------<br />I'm no expert, but I DID sleep at a Holiday Inn last night!

 

[12Footer]

Re: low compression 90hp L6 Marnier

It might just be a head gasket too.<br /><br /><br />------------------<br />I'm no expert, but I DID sleep at a Holiday Inn last night!

 

[ODDD1]

Re: low compression 90hp L6 Marnier

12 footer these motors dont have head gaskets

 

[corm]

Re: low compression 90hp L6 Marnier

Hey Ol'Joe,<br />I'd fix it now while it's cheeper to do. Run it and it could cost another $1000. Your choice as always.<br /><br />------------------<br />...have fun...corm<br /><br />cubic inches = power<br />power = speed<br />speed = FUN