Mopar 318/ 360 Fuel Pump Problems

Engines, Shafts, Steering, Struts, Rudders, etc.
Fastjeff
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Mopar 318/ 360 Fuel Pump Problems

Postby Fastjeff » Mon Jul 14, 2014 3:36 pm

This little bug bit me at last. Here's the deal:

"Weird" stalling and misfire under load, usually while on plane or getting there. Gotta be "White Gook" (ethanol formed, unburnable crap) I assumed--all last year. Nope. The fuel pump wasn't putting out enough, and why? The cam that works the arm is screwed up.

The below photo shows what the thing looks like. The keyway shown wears a 'slot' through the key on the cam, and the darn thing rotates on the cam instead of working the fuel pump arm. The solution is a major rip down of the front of the motor, or an electric fuel pump. I've opted for the later and will be installing it next weekend (along with the required safety off oil pressure switch).

Jeff
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Fuel Pump Cam Trouble.JPG
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"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington

ericinga
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Re: Mopar 318/ 360 Fuel Pump Problems

Postby ericinga » Fri Jul 18, 2014 3:04 pm

You know, that makes alot of sense.

I've been dealing with fuel supply issues. Occassionally, the motor will mysteriuously become starved for fuel after running for an hour or so. It has never really had full power or planed well. At full throttle, it won't rev higher than 3300 RPM. I've worked through the ignition system, carb install and tune-up.

There is a problem with tank debris that will be cured with time and filter changes. However, even a new fuel pump did not completely solve the supply problem.

I'm planning to stick a pressure gauge on it this weekend to determine the pump strengh. I'll also take the output line off and verify the flow rate into a quart jar.

Which pump and pressure switch are you installing?

Eric
Eric Spies
1989 32 SDFB
Twin 318s
Lake Lanier, GA
Marinette Boat

Fastjeff
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Re: Mopar 318/ 360 Fuel Pump Problems

Postby Fastjeff » Tue Jul 22, 2014 5:45 am

I used an Airtex E8251 Universal that I bought from Amazon. (It's USCG approved.)

The safety (oil pressure) switch is a three pronged deal for a mid-80s Dodge V-8. (There's several different types. Go to Auto Zone and check out the photos on their computer.) Use the prongs opposite of each other on the switch (normally open). Finally, being anal, I used a relay to operate the fuel pump (instead of the contacts inside the safety switch). I ground the coil circuit of the relay to operate the pump, with 12 volts right off the battery. I also used 10 amp in-line fuse.

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington