engine cuts out under load

[skip4926]

25 4 stroke merc idles fine but will cut out if i try to give it gas or put it into gear. the bulb loses stiffness as well, but it was just replaced. Even when I pump the bulb it will cut out when I give it any gas at all. Help!

 

[hkeiner]

Re: engine cuts out under load

It is normal for the bulb too lose "stiffness" when the motor is running. The motor sucks the fuel through the bulb and so there is no pressure in the line to cause the bulb to be firm. The bulb, however, should not collapse when the motor is running. If it collapses, that is a sign of a fuel line restriction upstream of the bulb.

If the motor does not respond to squeezing the bulb when the motor cuts out, then I would guess that it is not a fuel pump problem and more likely an ignition problem, link and sync problem, or a gummed up carb.

Just some thoughts...

 

[CharlieB]

Re: engine cuts out under load

The smaller 4 strokes have very small idle circuit passages that can clog with mineral deposits from fuel. They also have a plug/cap pressed in so you cannot get to the idle mixture screw until you drill a hole in the plug and pull it out of the carb body.

Cleaning the three small idle passages in the top of the carb and the idle screw passage should cure most of your immediate problem.

While you have the carb apart be SURE to check the accelerator pump as alcohol in your fuel will degrade the pump seal adding to your lean bog on acceleration.