1998 175 evinrude compression question

[hydrasports]

I checked the compression on my new leftover 1998 evinrude carbed motors, the port engine has 10 minutes running time and the compression is 115 on all cylinders except both bottom cylinders on each bank read 95,98 I almost had a heart attack and decided to check the other engine which has never been run, I got the same results, bottom cylinders on each bank both read 96 99 and the rest are 115. Is this common on engines that are not broken in yet? Im really nervous and sure hope its common. thanks

 

[clanton]

Re: 1998 175 evinrude compression question

The 92s, 95s, I have check were all the same, But I think I heard that some of these engines had lower compression on the 2 lower cylinders, Seahorse can tell us.

 

[hydrasports]

Re: 1998 175 evinrude compression question

Thanks clanton, i hope the ones you remembered hearing about included mine, anyone have experienced the same thing or have any opinions on this? than you

 

[hydrasports]

Re: 1998 175 evinrude compression question

Thanks clanton, i hope the ones you remembered hearing about included mine, anyone have experienced the same thing or have any opinions on this? thank you

 

[clanton]

Re: 1998 175 evinrude compression question

I have a OEM manual for those engines, and it said there may be a difference between the port and strb set of cylinders, but not more then 15 lbs. All cylinders should not have variation greater then 20%.

 

[hydrasports]

Re: 1998 175 evinrude compression question

thanks again, could compression numbers on new engines become higher after breakin ? Im thinking maybe the motors need to be broken in and then compression mite be closer to eachother? thanks