Need help identifying a part...

[Marian Claire]

I need help identifying a part. My engine is a UJR 77414 Year 1965 +-. I do not think this is original equipment since it does not show up in the manuals I have. It is attached to the copper line than runs from my engine to the oil pressure gauge. It is the black part with two prongs. One prong was fed from the + side of my coil and the other went to my electric fuel pump. I have had intermittent fuel pump problems and think this may be the problem. Please see attached pic.
Thanks for your help.

[David Masury]

It looks like an oil pressure safety switch.... since you have an electric fuel pump.. the switch is supposed to turn the electricity to the pump off when oil pressure drops below (approx) 9 lbs. Thus if something happens to your engine while running and it stops, your fuel pump will not continue to run overflowing the carb with fuel. When cranking the engine to start, it will produce more than the minimum oil presuure to allow the fuel pump to provide fuel to the carburator.

In all it is a good thing and the coast guard likes to see them on gas powered engines.

David Masury

[Marian Claire]

Need help

That was my first thought. But that leads to another question.
During the last few months, intermittently the fuel pump did not start (tick) when I turned the key. This last trip out we were motoring and I backed off to drop the hook and she shut off. The engine would not restart…the fuel pump did not tick. I checked for continuity across the prongs of the mystery part (now identified as the safety switch) and there was none. I bypassed the switch, connecting the pump directly to the coil and the pump ran. It ran much faster than in the past and did not slow down as the fuel pressure built (it used to) but it got us to our home port. The next morning I started the engine and it ran for a few minutes and stopped. The pump had seized. I am wondering if in bypassing the safety switch I allowed too much electrical current to the pump…basically frying it. Too much juice I guess, what do you think? Thanks for the info.

Dan

[Don Moyer]

Dan,

Not knowing what brand of pump you have, the Facet brand that we sell (and any other brand that I know of) is built for continuous duty and would not fail if connected directly to the positive of the coil for power.

Don

[Marian Claire]

Fuel pump

Thanks for the help. I have orderd a new pump , # 44, and oil pressure safety switch. What size fuse should I use and should I mount the fuse between the coil and the oil switch.
Dan

[Don Moyer]

Dan,

That would be a 5 amp fuse.

Don