i ran a compresion check on golfpimps boat after it was run out of oil, the boat runs ok...but i have 75 lbs on one, 120 lbs on the other, and the rest run from 100 to 108 lbs. Boat still runs good, starts everytime and will plain out with good power....whats my next method of attack...and opti said something of preforming a leak down test, what is that testing? I do have some knowledge and have rebuilt a 150 mariner after a blew a rod in my dads boat when i took it out in high school while he was out of town but that was 15 years ago. anyhelp would be appreciated. Thanks

If you have 75 lbs there is no reason to do a leak down test as you have problems at least in one cylinder. You can probably see evidence of it by looking into the cylinder through the spark plug hole but you need to tear it down.
I'd guess that you might have main bearing problems too if it was run for any length of time without oil.

thank you david, what is a leak down test?? i did not look through it but i will. thanks. would that be the cuase of 75 lbs in one cylinder?

thanks again for the help,

gwb

I'm not an expert but a leak down test can tell you where you are loosing compression. The test is run at top dead center when all valves are closed off. There will always be some leaking but by measuring the amount of pressure loss over a fixed time and comparing to the other cylinders you can tell which ones have problems.

The tester uses the spark plug hole.

I am guessing the 75 lb cylinder has lost some of the ring surface. I'd bet you can see some cylinder scoring on the cylinder wall.

i think your right thanks for the help

anyone else with suggestion of fixing this problem before i get started, called the marina....said 3000 grand for block and 2000 grand to put it in...go figure, 5000 dollar fix on a 7000 dollar boat got to be another way.

Well...
I'd call Mike Halfman in San Marcos, he'll give you the good, better, best options.

Good: replace the one piston and rings, you'll get some servicable life, but nothing lasting a long time.

Better: replace all six pistons/rings with new. *could* last a very long time

Best: New/reman powerhead, about the cost you described.

If the tech is good and throrough, there is a very fine line between good/best. If he's sloppy, and cheap (pookey instead of gaskets) then you'll be doing it again soon.

Call me (512) 353-1854 Outboard Shop in San Marcos.

Boat is in the for sale section