Posts: 400
Location: Metro | EsoxRookie - 10/26/2014 9:40 AM
FWIW I would have agreed with the opinions on the compression readings until I ran across this in a service manual for my motor:
"In order to maintain proper cylinder temperature on 3-cylinder and V6 engines, Yamaha varies the cylinder head volume on some models. A V6 will normally show the highest compression on cylinders 1 and 2 with cylinders 5 and 6 showing the lowest reading..."
It goes on to say that "A variation of of more than 15 psi between two cylinders indicates a problem...".
I didn't see any mention of the motor brand. The 105-120 variance on that motor may well be within spec if its a Yamaha. Not perfect, but still within spec.
Thanks for posting this. When I took a look at the boat this week the guy said it runs great but they have a kid so need to get rid of it. He said he would be willing to take it too a lake for a test drive and also I told him I would probably want to take it into a mechanic just to get a run through.
Somewhat of a relief to see one good comment about the compression. And it is a Yamaha so.... I guess we will see what the mechanic says. |