mechanical fuel pump issues

[CheapboatKev]

1968 3.0 4 banger with mechanical fuel pump. This is the "top up" model with the seperate fuel filter bowl.
I disconnected the fuel line to the carb to see if any fuel was getting there..

nothing.


I remove the pump from the motor, bump the rocker arm/piston by hand, and fuel pumps as it should.

Also, on the bottom right hand side is the brass fitting that acts as an overflow to the carb, if I put a finger on there to close it off, I can't bump the lever by hand anymore..too much pressure it seems..I am sure thats normal..

So am I correct to think that the lever that is bumped by the crankshaft is worn to a point of not making contact?

Thnks in advance...love to get this project on the water soon, all the other Starcraft guys are passing me up!!

 

[Bt Doctur]

Re: mechanical fuel pump issues

That or the cam is shot. reinstall and test from a remote tank.might be a fuel feed or tank problem

 

[CheapboatKev]

Re: mechanical fuel pump issues

Thanks BT...

I should have stated that both "tests" (on the engine as well as off bumping by hand) that I had clear fuel lines and using a remote jerry can with new fuel.

 

[CheapboatKev]

Re: mechanical fuel pump issues

Well..
I bought a used fuel pump from a marine salvage yard today.
Same issue of not pumping.
I will have to verify tomorrow, but think it's safe to say the "lobe" on the cam is worn..

Now I will explore electric fuel pumps as my only options. The research I have done thus far has me thinking that I need a low pressure (<5psi) for my 4 banger.

What is involved with the "Oil sensor switch mandatory"
Does this act as a kill switch when/if the motor dies???

I also assume that there is a difference between marine/auto elect pumps as well?


Thanks guys...

 

[Don S]

Re: mechanical fuel pump issues

Before you start going electric, hook up your remote tank and remove the line that goes from the pump to the carb.
Hook a hose to the fuel pump and see if it pumps fuel when you crank the engine over. Make sure you have gas too the pump. If it hasn't started pulling fuel from the tank in a few cranks of the engine, then it's time to take the pump off the block and look/feel to see if the cam lobe for the pump is going up and down.

 

[CheapboatKev]

Re: mechanical fuel pump issues

Don S thanks for the input.You've always posted for my issues..I appreciate it...

I have done all of that cept for having someone bump the motor over while I lay in there and look for the lobe...In fact it pumped while I had it off and pumped her by hand...put it on and nuthin..

It would be very rare for the lobe to be that worn wouldnt it?

 

[CheapboatKev]

Re: mechanical fuel pump issues

heres the deal, I guess the pic says it all.
That bright shiny non lobe area is where it once pushed the mechanical fuel pump arm..

 

[maxh]

Re: mechanical fuel pump issues

Fyi, the electric diaphram fuel pump from napa works fantastic on my 4 cyl... Disclaimer: using non marine parts may cause you to go boom