Fuel Pump for gassers

[Harry Babb]

I want to share my recent fuel pump replacment/modification with you gasser guys and get your opinion. I have 454 Marine Power with Carter electric fuel pumps.

At the end of last summer one day I was fishing just off of Fort Morgan for Spanish. Up until that day I had never experienced a problem with my fuel pump.

I was going up current from a rig, shutting down my engines and drift fishing back past the rig then cranking up and doing the same thing all over again.

After a few times of doing this my starboard engine would crank, run for a few seconds then die. The fuel pump was not delivering fuel to the carb. I finally had to remove the fuel line from the carb and suck fuel thru the pump to "get it primed" then we ran for home. As long as I did not shut off the engine it would keep running just fine.

The port engine never faulted at all. The fuel tank vent was not obstructed and the filters was brand new.

Obviously I had to replace the fuel pump but a friend told me that he had noticed that fuel pumps were failing prematurely on the Marine Power engines as well as some of the Mercruiser engines.

His recommendation was to install a "Bypass Type" fuel pressure regulator in the system so that the pump could circulate unused fuel back to the tank thereby keeping the pump cool and extending its life.

I followed his recommendation, installed the regulator and a 3/8" return line back to the tank. I found that the fuel pump could pump 7 PSI but the engine would operate at WOT at 2-1/2 PSI so I set my regulators to 3-1/2 PSI and you would not believe how much fuel is being returned back to the tank. Now the entire fuel system stays cold.

So what do you guys think????

Harry Babb

[Bruce]

Harry,

If it is the Carter pump that has the 3 studs that hold the vein rotor cover on then they have a very, very fine mesh screen in them that will clog over time. You can pull the cover off, clean and reinstall.

It doesn't matter if there is a filter before it.

Also as the veins in the pump wear, the priming and pumping capacity dwindle against a head.

If it was a vapor lock problem, then what you did will help. So will insulating any metal fuel lines and isolating mountings from the block.

That pump is a very high flow pump and it will return quite a bit of fuel to the tank.

Just don't make the mistake of connecting the return to the 3rd pickup line.

It will make the pump fight against itself and about half full tank the engines will start cutting out.

[Harry Babb]

Bruce
Thanks for the reply. Your right, it is the Carter pump with the 3 studs that mount the pump.

I did not realize that the pump had the fine mesh screen until after I replace the pump and disassembled the old one to have a look see.

I actually drilled and tapped a new hole in the fuel pickup plate right next to the distribution block to use for the return line. Due to limited space I drilled and tapped 1 hole then ran the return lines to a tee that dumped the returned fuel into the tank. I was unsure if this would work or if it was a good idea and I have yet to test it out on a long trip.

I would have loved to put mechanical pumps on these engines but the blocks were not machined to accept mechanical pumps so I guess I am stuck with these electric pumps.

Have you seen many of these pumps fail prematurely or better yet do you know what the life expectancy is for these Carter pumps??

Thanks
Harry Babb

[Bruce]

I'd toss em after 1000 hours or 6 years.

They are good pumps.

The way you did the return lines should work just fine.