Re: whats the right compression on old 'rude
Welcome to Iboats, willjhand!<br /><br />Although there's no published numbers for your engine, 80/86 is pretty low. Good as new comes out about 120, and normally we see 90-110. But I don't think that's your slow problem. Try pulling each spark plug lead off (with insulated pliers) while running and note the difference. That is to say, see if one cylinder isn't providing as much power as the other.<br /><br />Often these old engines are badly carboned up and a little decarb solution will help get the compression up by freeing a couple stuck rings. It's worth a shot. Apply the stuff directly into the cylinders through the spark plug holes. Check out the FAQ forum for details.<br /><br />There's good reason they never published compression numbers - there's too many variables. Altitude, whether the engine is hot or cold, how much oil is left on the cylinder walls, how many cranks you give it, even barometric pressure all affect the results. Not to mention no two compression testers ever seem to agree.
