Compression Questions

[montana]

Could someone please advise what the correct compression would be on 1992 Outboards (Yam, 250). I'm told it tested out at between 95 and 103 on all six cylinders, with none below 95. Thanks.

 

[MGuckin]

Re: Compression Questions

You will get more responses and advise in the outboard section, however, compression is a little low, but servicable for its age.

 

[Capt Ken]

Re: Compression Questions

Compression is in direct relation to cranking speed. If the compression is within 12% from the highest to the lowest, no problem. I've also seen compression gauges differ as much as 30 psi.

 

[sony2001]

Re: Compression Questions

12% is a bite strict. I think the FAA people accept 20%.

 

[geriksen]

Re: Compression Questions

those readings mean it has not burned a piston today<br />maybe tomorrow..........

 

[dick]

Re: Compression Questions

You may want to try the outboard forum for other opinions but for those loop charged engines 90 to 110 psi is normal.