Posted by Mike on February 16, 2004 at 10:23:42:
In Reply to: Steam & Fuel in Exhaust posted by Bill on 21:29:19 02/15/04:
Certainly check the compression before you strip. If it is zero in just one or two cylinders I would suspect a stuck valve before a cracked head or head gasket--especially if the bad cylinders are not adjacent. What do your plugs look like? The deposits on the plugs will help you locate the cylinder with problems if it is just one cylinder. They might also point to a fuel problem.
For a stuck valve, Don Moyer suggests Marvel Mystery oil (or something similar). Add some to the oil, apply directly into the cylinders (with the plugs out) and turn over the engine. Let it sit for a while and run the engine to see if you can free it up.
Do you have a waterlift muffler and did you have to crank the engine a long time before it started? If so you may have filled the muffler causing water to back up into the valves forcing them open.
I would also look at the carburetor. A bad carb float, a clogged well vent jet or dirt in the float valve will give you similar syptoms (i.e. runs rich with white exhaust & fuel slick behind exhaust, dies at low throttle).
I have had almost exactly the same symptoms with a bad carburetor float on a different type of gasoline engine. Tried all kinds of things until I figured it out.