Merc 228 hard start when warm

[rheacox]

New boating season, new boating problems. I have a 1983 cobalt with the SBC 305 quadrajet configuration. The boat starts pretty well when cold however once its warmed up, it becomes hard to impossible to restart, had to paddle it across the lake after i cranked it till the battery died last night... It also pops under hard acceleration like its running lean. I've read that the timing could be set incorrectly. It isn't the starter and it is getting plenty of gas when i pump the throttle. Also, when cranking hot or cold, it seems to grunt, like the battery was weak, however the battery was new last year. Any advice and help would be great. Thanks.

 

[rheacox]

Could it also be the thermal choke?

 

[harleyman1975]

If you run the engine to temp and shut it off will it restart right away?
Could your carb be leaking gas into the engine when it is sitting? Fuel pump bad? Anti siphon valve sticking open? Dirty needle and seat? Check to see if when you shut warm engine off if there is gas dripping into the throat of the carb. The more I think about it the more I think that you have a needle and seat problem.

 

[rheacox]

Carb could very well be leaking gas. That was one of the things the mechanic at the marina and I came up with today. I take back what I said about the starter, I think its getting heat soak, for all I know it could very well be the original starter from 1983. I know the quadrajet is prone to leaking through the plugs pressed into the casting. I'll seal them up with some epoxy and change out the starter and see what happens. Engine will restart right away, new fuel pump was put on last year and the anti-siphon valve seems alright.