Fuel pump does not pump to carb Mercruiser 4.3

I have a 1991 Mercruiser 4.3 2 bbl that isn't getting gas to the carb. The last owner didn't properly treat the gas and it sat for 8 months with 1/4 tank of gas.

I added Stabil and 10 gallons of gas, then I replaced the in-line filter and the in-carb filter (which was completely clogged), but it quickly ran out of fuel, so I replaced the in-line, fuel pump and in-carb filters and now it doesn't get any fuel to the carb. I removed the line from the pump to carb and it is clean The in-line filter fills with gas as soon as I crank it over, but nothing comes out of the tube at the carb end (I ran clear tubing to a catch bottle).

Since the filter before the pump filled, I assume that the pump is good, but should I replace it?

Re: Fuel pump does not pump to carb Mercruiser 4.3

tone_searay185 said:

I have a 1991 Mercruiser 4.3 2 bbl that isn't getting gas to the carb. The last owner didn't properly treat the gas and it sat for 8 months with 1/4 tank of gas.

I added Stabil and 10 gallons of gas, then I replaced the in-line filter and the in-carb filter (which was completely clogged), but it quickly ran out of fuel, so I replaced the in-line, fuel pump and in-carb filters and now it doesn't get any fuel to the carb. I removed the line from the pump to carb and it is clean The in-line filter fills with gas as soon as I crank it over, but nothing comes out of the tube at the carb end (I ran clear tubing to a catch bottle).

Since the filter before the pump filled, I assume that the pump is good, but should I replace it?

Click to expand...

Ayuh,... There's an extremely Good chance that both the Carb, 'n the Fuel Pump are full of the same crap that was in the filters,....

Re: Fuel pump does not pump to carb Mercruiser 4.3

Thanks, I'll rebuild the carb, but do I need to replace the fuel pump or is there a way to rebuild or clean it? I'm guessing that the outlet may be clogged.

I'm also adding a water separator filter since it doesn't have one, where is the best place to put it? Just outside the engine bay would make it easy to get to but then it might get bumped by something going in that area.

Re: Fuel pump does not pump to carb Mercruiser 4.3

There is also the anti syphon on the tank and fuel screen in the tank that may be full of crap also, you may want to replace the anti syphon and look/clean the screen

Re: Fuel pump does not pump to carb Mercruiser 4.3

tone_searay185 said:

Thanks, I'll rebuild the carb, but do I need to replace the fuel pump or is there a way to rebuild or clean it? I'm guessing that the outlet may be clogged.

I'm also adding a water separator filter since it doesn't have one, where is the best place to put it? Just outside the engine bay would make it easy to get to but then it might get bumped by something going in that area.

Click to expand...

Ayuh,.... Anywhere 'tween the Tank, 'n the Fuel Pump,...

Re: Fuel pump does not pump to carb Mercruiser 4.3

Just run some fuel or air through the line. I bet you can assist it through the pump too. I'd also remove the line back at the vent and before the pump, then blow air or fuel through the fuel delivery system once the tank is clean. That should push out any crud in the line. Or replace the line if you want to be perfect.

Re: Fuel pump does not pump to carb Mercruiser 4.3

Great idea about pushing air through the line, since the pump is pulling gas to the in-line filter hopefully the tank side is ok. I'm adding a water separator, so I'm replacing much of the fuel line anyway and the line from the pump to carb is clean. I'll pull the line exiting the pump and add a brass fitting and some clear line so I can see the junk coming through...otherwise I'll be replacing the pump too.

I'm rebuilding the carb since it is just a 2 BBL and the adjustments are pretty simple.

Thanks for all the info!