1993_yamaha_stern_130
Member
"Hi All,
I ran a compressio
"Hi All,
I ran a compression test on my three litre I/O yesterday. It is a yamaha assembly - but I believe it is a GM engine. I ran the test dry - I did not add any oil to the cylinders. I let each cylinder compress three times - where the pressure topped out. Cylinder 1 (close to the front) 210psi on first two attempts - then read 140psi on the remainder of the tests. Cylinder 2 - 130psi, cylinder 3 125psi. The cylinder nearest the stern (cylinder 4) initially read 210psi - then stabilized at 135psi for the remainder of the attempts. When I compressed the schrader valve (spelling?) to release the pressure at the end of each test, it seemed like a water spray came out. Question: What do these results mean ? Also, why did cylinder 1 and 4 have such increadibly high readings on the initial tests ? Does these test results mean that my block and head are not cracked, and that I probably have water coming in via the exhaust manifold ?
Any responses will be sincerely appreciated - thank you."
I ran a compressio
"Hi All,
I ran a compression test on my three litre I/O yesterday. It is a yamaha assembly - but I believe it is a GM engine. I ran the test dry - I did not add any oil to the cylinders. I let each cylinder compress three times - where the pressure topped out. Cylinder 1 (close to the front) 210psi on first two attempts - then read 140psi on the remainder of the tests. Cylinder 2 - 130psi, cylinder 3 125psi. The cylinder nearest the stern (cylinder 4) initially read 210psi - then stabilized at 135psi for the remainder of the attempts. When I compressed the schrader valve (spelling?) to release the pressure at the end of each test, it seemed like a water spray came out. Question: What do these results mean ? Also, why did cylinder 1 and 4 have such increadibly high readings on the initial tests ? Does these test results mean that my block and head are not cracked, and that I probably have water coming in via the exhaust manifold ?
Any responses will be sincerely appreciated - thank you."