Re: 115 hp 1980 Merc carburetor fix advanced -WMK-28
The symptoms?<br /><br />Power packs replaced last year.<br /><br />The motor has been erratic -- always idles ok, first it would go to 1900 rpm and start cutting out.<br /><br />Cleaned everything out including the carbs and it ran fine for a day (5000+ rpm and zoom), sit up for a week and it would idle but not much more.<br /><br />Then flushed the tank again, checked the hoses again and it ran fine for an afternoon. Then sit for a week and the same old problem.<br /><br />Bottom line is it runs great at low speed but is erratic at all others despite recent carb cleaning. Or what I paid for was a carb cleaning....<br /><br />Mechanic showed me slack in carb body where there was air between the butterfly shaft and the carb body and said that was the most likely source of an air leak, could keep it hard to start and erratic otherwise. <br /><br />His thought was that a washer and an o-ring between the spring and the carb body could shut off most of the air. Showed me several used sets where the wear was greatest on the bottom.<br /><br />LATEST UPDATE -- We found that the tube that recyles gas down the right side of the motor near base had a leak and was spraying -- replaced. Cranks up OK and goes to 4500 rpm. Lake test pending.<br /><br />If my mechanic is the problem, that is the easiest part to replace.
