Mercruiser stalling issues .

[muskrat808]

Hi- My 1972 Mercruiser 140 hp starts up and runs fine when started cold . It runs fine for 30 -60 min or so then will start to run rough and stall out if at idle or lower speeds . Then it will only start at full throttle and stall when shifted into gear .Carb was rebuilt a few years ago ,plugs ,dist, rotor electronic ignition all fairly new . Main fuel filter and fuel water separator changed yearly . I,ve read about shift switch issues causing this but I assume that would also happen when cold .Ready to replace with new rebuilt carb . Any suggestions ? Thanks

 

[Niels45]

I have the same problem. I’m following what the solution is....

 

[wellcraft-classic210]

Sounds like debris in the float bowl of the carb could be a likely cause cause.

Learning to clean the carb and passages / replacing gaskets would be your most practical option.

Monitoring the fuel pressure and ensuring its OK would support the carb problem.

If your up for it -- we can walk you trough the steps.

 

[tank1949]

Sounds like debris in the float bowl of the carb could be a likely cause cause.

Learning to clean the carb and passages / replacing gaskets would be your most practical option.

Monitoring the fuel pressure and ensuring its OK would support the carb problem.

If your up for it -- we can walk you trough the steps.

You may also have an anti-syphon device causing issues. I had similar on a Proline.

 

[muskrat808]

So -a couple more questions -What issues would an ant-siphon device cause ?And why would debris in float bowl only cause problems after running for awhile and not at initial cold start up ? Thanks for input .

 

[muskrat808]

So ,Niels 45 it looks like were on our own here . I thought I would get more responses and ideas here . Still think its got to be a heat issue since problem develops after running for an hour plus . Thinking of just replacing carb and seeing how that works . Anyone out there use National carbs or Flying Fish Carbs ( both online ) Thanks

 

[Niels45]

I’m changing my electronic ignition kit for the original ignition with points. See if that changes anything. My boat meganic things it might be the float level in the carb. But why doesn’t it stall when cold? I keep you posted.

 

[Niels45]

I’m changing my electronic ignition kit for the original ignition with points. See if that changes anything. My boat meganic things it might be the float level in the carb. But why doesn’t it stall when cold? I keep you posted.