2014 90hp 4 stroke compression

[carolina115]

Looking at a 2014 90hp 4 stroke and have a concern. There was what was thought to be a piston issue because of low compression. After piston work was done compression was still low so looked at valves and there was an issue with them and they were replaced. Compression went to 260 which seems to be way out of whack to me. Has anyone ever heard of compression being that high and what could cause it. I know it could be carbon build-up to some degree but I suspect it is more than that. Thanks, guys.

[panasonic]

What were the other cylinders reading? Did they use the same gauge to test all of them?

[carolina115]

All of the cylinders tested at right at 260 and yes the same tool for all cylinders.

[99yam40]

how many cylinders had low compression?
how many pistons were replaced?
how many valves were replaced?
how many have high compression now?
you give very little info.

usually when pistons and valves are replaced the carbon is cleaned from the combustion chamber afterwords,
so i would not be worried about carbon.
4 strokes have higher compression than 2 stroke, but I do not know what your motor should have.

Edit: I see you posted they all are equal. so you should be good if they used OEM parts

[carolina115]

Thanks for the reply and not sure about the number of valves and pistons but believe all were replaced and yes they all have the same high compression. Just never heard of any that high.

[carolina115]

All parts came from yamaha outboard parts