fuel restriction or fuel pump

[skelly]

1979 Wellcraft 470 Mercruiser 2/B Rochester carb ..Went out on the bay last week and started to drop RPMs (Just a lil )then pick back up again, ran about 10 miles, As we slowed down to fish it started to run rough and when i put it in nutral it cut off and would not restart. (No fuel in carb,) so i pulled the bell off the fuel pump and it was dry, filter clean,I would have though that gas would have gushed out, fuel vent was clear, So i sprayed some WD40 in to the Fuel pump and this did the trick to get me started, So we headed back across the bay, Ran good untill about 1 mile out ,started to break down and run rough but we made it to the ramp, put her in nutral and that was all she wrote , Went home and did some work on her. Cleaned filter in fuel pump, filter in carb, Fuel water/Sep filter, new pionts & cond. Went out to fish today , Trolled for about 3 hrs with no trouble, But when we stared back in I had the same thing happen as last week. Removed the fule pump bowl and it was dry again, WD40 worked again (Is this right ? Should fuel flow back to the tank? Or is my fuel pump going bad? I will recheck my ANTI,S/V but I think it is OK. Thanks in Advance for your HELP.........

 

[180shabah]

Re: fuel restriction or fuel pump

Well, the fuel certainly shouldn't run back to the tank while the engine is running. Start checking for restrictions between the pump and the tank, and also in the vent line.

 

[Haut Medoc]

Re: fuel restriction or fuel pump

Did you replace the water separating fuelm filter or just drain it?.....
They do not last indefinately....​

 

[Don S]

Re: fuel restriction or fuel pump

Testing the fuel pump pressure is one test, along with this test should find any fuel related problems.

 

[skelly]

Re: fuel restriction or fuel pump

Did you replace the water separating fuelm filter or just drain it?.....
They do not last indefinately....​

This boat never had a fuel/Water/Sep , I Installed one, Today I Checked the Pickup tube and petcock shutoff valve that is atatched to it, (Looks Good to me) It apears that it dose not have a Anti Siph/check valve, I though the square thing that the pickup tube screws in to was it. So every thing looks good from tank to just befor fuel pump to me...........Thanks

 

[Haut Medoc]

Re: fuel restriction or fuel pump

Either ya gotta perform Don's tests or replace the pump, which may or may not be the problem....
If it is the original pump, I would replace it, but that's just me.....
I'd do the tests first though.....​

 

[skelly]

Re: fuel restriction or fuel pump

Either ya gotta perform Don's tests or replace the pump, which may or may not be the problem....
If it is the original pump, I would replace it, but that's just me.....
I'd do the tests first though.....​

I think your Right, It is the original Pump and i don't want to get stuck out on one of those long 10/15 mile fishing trips. (money well spent) I could do the test and it could still go bad down the road, After all it is 28 years old and not too $$$ .I will keep you posted, Thanks .

 

[skelly]

Re: fuel restriction or fuel pump

Testing the fuel pump pressure is one test, along with this test should find any fuel related problems.

thanks for responing, This is great Info