1983, 70HP Mercury fuel problem

[gene6868]

There is no fuel entering the cylinders. Trouble shooting so far indicates I have fuel in the carbs but no evidence that it is getting into crankcase. When engine failed I was running at full choke, since then has not fired at all. It appears to be a reed valve problem, but to check the reed valves (mounted on the crankshaft) the repair manual states that the power head must be overhauled. If any of you have had a similar problem would appreciate any advice or comments.

 

[JB]

Re: 1983, 70HP Mercury fuel problem

Hi, Gene.<br /><br />Reeds for all cylinders fail at the same time? Not likely. That would be like having 4 flat tires at the same time. <br /><br />The reeds are mounted on the bearing carriers that seal the various crankcases from each other, not on the crankshaft. That engine will start and run on one cylinder if it has spark, a correct fuel/air mix, scavenging and compression.<br /><br />Running on full choke? Carbs were not feeding a good mix before the engine quit completely.<br /><br />Have you confirmed that you have a hot, blue spark on all plugs?<br /><br />Have you squirted some fuel mix into the carb throats when trying to start?<br /><br />Have you done a compression check?<br /><br />Let us know what you find out.<br /><br />Good luck.