Stuck exhaust valve?

[rasteer]

I think I have a stuck exhaust valve. I was running the engine with a garden hose during spring launch and made water come out the Carb. After changing the oil a few times the engine started and warmed up ok. While moving the boat, I could not get full power, and after about a two hour motor trip the engine would not idle. While testing things; elect, fuel, etc, I got water out of the carb again (sea water). This time I found no compression in #2 cyl. Should I now pull the head and plan on rebuilding or try MMO and other things. The engine is a 1981 and does not appear to have been well maintained. This is my first full year with the boat, so history is sketchy.

--Rick

[Don Moyer]

Rick,

Unfortunately, we only have a rather short list of ways to unstick stuck valves. If the valves aren't stuck too hard, we can sometimes free them by bending a small common screwdriver in such a way as to work it into the spark plug hole to press down on top of the valve. This is quite easy to accomplish in the case of intake valves (which are directly below the spark plug holes), but the exhaust valves are off to the side and very difficult to reach. To make matters worse, it's the exhaust valves that usually stick.

The only other technique with which we've had a small amount of success is to remove the valve cover and grab the very bottom of the valve stem with a needle-nose vise grip and attempt to rotate the valve.

If more than one valve is stuck and/or they don't yield with the bent screwdriver, it's usually necessary to remove the head.

After freeing up the valve, use Marvel Mystery Oil in the gasoline at a rate of at least 8 to 10 ounces per 10 gallons of fuel to keep the valve(s) free.

Don