Posted by st on October 02, 2003 at 14:47:07:
I recently found bad compression in the #2 cyl. So I thought stuck valve, probably. I take the head off and the values are not stuck, but the #2 cyk. exhaust value is messed up. After I got it out what it looks like is that somebody took a hammer to it...(I got the boat recently). I replaced the valve, reset the tappet clearance which was way too big, checked the other valves, they were pretty close. Thinking I was done I replaced the head gasket with the 2 steel reinforced graphite gaskets from Moyer Marine and close it up.
Now all four cyl.s show about 60 lbs compression, even the ones that used to be good... hmmm.
I took it apart again, the head gaskets look good. I did not use sealer on the head gasket but I gunked up (with permatex) all the other gaskets that I'd come across; manifold to carb., manifold to head valve cover and the 2 cooling water crossover tube gaskets.
Then I went thru tightening the head with the graduated torque sequence. And checked the compression again: no change. The compression was still around 60 on all cyls.
This is an early (1960) model engine.
All the spark plugs were tight.
Three of the four cyls. had good compression before I started, and I'm thinking about an outboard.