Mercruiser 3.0 stalls after 30 min

[rupp0003]

1989 merc 3.0 starts fine, runs fine for about half an hour at any speed or rpm then starts to miss and will eventually stall. Fuel dripping from flame arrestor but only once rough running starts. Will sometimes restart after a few minutes and run ok other times will continue to run rough and stall.

Are there any members out there that might have some insight into what the problem might be?

 

[NHGuy]

Re: Mercruiser 3.0 stalls after 30 min

You probably have a sticking carb float. There is also a possibility that the fuel pump is making too much pressure.
Weird that it takes half an hour to do it though. Check your carburetor.

 

[airshot]

Re: Mercruiser 3.0 stalls after 30 min

Possible water in fuel, or i agree with stuck float. Does it happen after you hit a wave or boat makes a sudden movement. Check your water seperator filter and fuel for water.

Airshot

 

[rupp0003]

Re: Mercruiser 3.0 stalls after 30 min

Would a sticking carb float require a rebuild. Or is there a way to effectivly clean the carb out.

 

[rupp0003]

Re: Mercruiser 3.0 stalls after 30 min

Thanks I'll check the fuel filter too. What happens is it starts missing the odd time hear or there, Becomes more frequent, then stalls out.

 

[taylorsfields]

Re: Mercruiser 3.0 stalls after 30 min

depending on the set up, you should be able to adjust fuel pressure by ordering (or making) a different thickness gasket between the mechanical pump and the engine block.

A thinner gasket is more pressure, a thicker gasket is less pressure.

Has it always had this problem? Or did it start after a rebuild/even/activity?