Fuel pump on it's way out ?

[Rod Holder]

1978 470 Mercruiser (rebuilt but re-used fuel pump)<br /><br />Hi,<br />Three times now (after rebuild) while returning from a day out (around 3 hrs run time) the engine will start to start to surge. Starts out very slight but within a few minutes it is as if the fuel line was closed off and re-opened over and over. Eventually, even if the throttle is backed way off, it will die and not restart (fire up the kicker and call the wife time). And I swear each time it has been after a following sea pounding.<br /><br />I have changed all filters/seperators and backflushed the pickup tube with compressed air on the tank (plastic)after the first time and switched over to Pertronix (module/coil/wires)after the second. Other than this problem it runs like a top.<br /><br />Any advise much appreciated......RH

 

[Don S]

Re: Fuel pump on it's way out ?

You might check your fuel tank vent. If it's plugged up, your fuel pump will not be able to pull fuel out of the tank. Next time it starts to die, remove the fill cap and see if the engine picks back up.

 

[elpaso]

Re: Fuel pump on it's way out ?

What will restart engine - a cool down time ? Refill fuel tank ?<br />What do you do to make it run again. <br /><br />When it stops - have you tried a shot of starting fluid, which will<br />tell you fuel or electrical problem. Did you replace the coil - pull and check the pickup tube?

 

[Rod Holder]

Re: Fuel pump on it's way out ?

Thanks guys,<br />The first time it happened I tried removing the filler cap and it did not help.<br /><br />I did get it to fire up and run at idle speed by squirting some fuel directly into the carb before trying to re-start. While I was there I checked to see if the accelerator pump was working and it would squirt while opening the throttle.<br /><br />The ignition is all new (as described above) <br /><br />Elpaso makes a good point with asking about what it takes to run again. This always happens at the end of the day when I have around 1/2 tank or less. A hole on the pickup tube ? I had tried to crack it loose and check it last summer but after 1/4 turn it got tight again (as in if turned any further it would snap and I would be cutting the floor open to replace the tank) so I hit it with a few blasts of compressed air. I don't think a blow torch is recommended there.<br /><br />Maybe I'll drop the nose of the boat down as far as possible to get as much of the tube exposed as possible and draw some vacuum.<br /><br />Thanks for the ideas.........RH

 

[Boomyal]

Re: Fuel pump on it's way out ?

RH, it's not uncommon for fuel pumps to go exactly as you are experiencing. The pump would be my bet. I had that happen on mine so I bought a new pump and threw it on the boat. Sure enough, several trips latter, I had to sputter over to a dock and change the pump. Was glad to have it on board. <br /><br />I had to get towed back in once before, took the pump apart and it looked perfect. Three trips latter the above happened.