40 hp Mercury will not idle

[chrissavell]

I have a 1988 40hp Mercury Classic, 4-cylinder, 2- carb's which will not idle and is very diffuclult to start. Repair shop kept the boat six weeks and told me it was on running on 3 cylinders. Also told me carb's were clean and properly adjusted. Mentioned something about a possible crack in the exhaust area. Motor runs good at high idle or throttle. Motor also uses more fuel than normal. Mechanic gave up and said he couldn't figure it out. Any insight would be appreciated.

 

[hondon]

Re: 40 hp Mercury will not idle

You have got to get the basics established.COMPRESSION,IGNITION,FUEL,EXHAUST,.You ca'nt have an exhaust issue because you do just fine off idle.How is the compression?

 

[Chinewalker]

Re: 40 hp Mercury will not idle

Any eveidence of water in the non-firing cylinder? Might be as simple as a blown exhaust cover gasket - not uncommon in the 4-cylinder 44-cube Mercs...<br />- Scott