Fuel pump, Mercrusier 4.3 1988

[Otis007]

I have a1988 Cobalt 192 Mercruiser 4.3 Alpha One. I removed the fuel pump because the neoprene line that runs to the carb was clogged. The clog goes all the way into the nipple in the pump. How do I clean that? I don't want to poke a pin in there for fear that I'll push the gunk into the pump. Also, why are there two lines going to the carb? I understand one inlet line from the fuel filter and one outlet line to the carb. But why two lines to the carb?

 

[tpenfield]

:welcome: to iBoats . . .

To unclog the line you could use a small drill bit and 'manually' screw it into the nipple just to the length of the nipple to see if you can free it up. The second line to the carb is a return line in case there is a fuel overflow issue at the carb.

You may want to take the fuel pump off to really give it the once over though, instead of just trying to make do.

 

[Bondo]

The clog goes all the way into the nipple in the pump. How do I clean that?

Ayuh,..... Welcome Aboard,...... Unscrew the nipple from the fuel pump, 'n push the crap out of it,.....

Also, why are there two lines going to the carb? I understand one inlet line from the fuel filter and one outlet line to the carb.

The 3rd line should be transparent tygon tubing, so you can see gas in it, when the diaphragm ruptures in the fuel pump,...
It directs the gas spill into the carb, rather than into the bilge,.....

 

[Otis007]

Thank you. I was hoping the clogged line explained my stalling problem. I guess it’s back to the drawing board for that. The boat stalls, but then I can start it right back up. (actually the problem has gotten worse over time, now it doesn’t start back up. It cranks but doesn’t start, like it has no gas) Sometimes it stalls at WOT sometimes at idle. It doesn’t matter how much load is on the engine. The engine temp doesn’t matter either.

 

[Rick Stephens]

The fix is to go through the fuel system. Pull your fuel water separator, dump into a clear container. Anything but clean gas in it? Pull the inlet filter off the carburetor, clogged up? While the line is off the carb, poke it into a plastic bottle and crank the motor - pumping fuel? If any of the above shows crud, then you may need to rebuild the carburetor and maybe pump out and clean the fuel tank.

 

[Otis007]

Thanks Rick. I’ll do those things next weekend. One thing that has me scratching my head is this: the engine runs great, then stalls. It doesn’t run rough or sputter. It just dies.

 

[Rick Stephens]

Of corse,possible some sort of ignition issue,but esy to test if you can repeat the problem. When it happens, pull the flame arrest or off and have someone pump the throttle. If there is fuel in the carb the throttle pump will squirt gas. If there is gas, then something else going on.