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Oil Pressure Switch ?

W

wblazer

Regular Contributor
Hi Guys,
Reading over the forum today and notice a reply about oil pressure switches. I have a 1986 4.3 with an electric fuel pump. The pump was on the boat when I purchased it three years ago.The pump was a cheap auto style and was not putting out the proper
pressure. I replaced it with a Holley red marine style that works fine. The pump is not wired into an oil pressure switch. Some one said that it was a Coast Guard regulation that an electric pump has to be wired into an oil pressure switch. I agree that without this a real problem could happen. What do I need parts wise to wire and correct this problem. Thanks for any help given.
 
you need the port available just foward and above the oil filter to install the pressure switch. If your block is not provisioned there ,locate the oil sender and "T" off that . .Standard auto part # PS126 or PS 127 will work.
 
Of course you realize that the switch is to kill the fuel supply should the engine stop due to ?????.
So the switch will be N/O (normally open)!
I'd encourage the use of one that incorporates screw down terminals.......
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hobbs_diag.jpg


..... appose to push-on.
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N/O means that the oil pressure must come up before this circuit closes............. which creates the need for a "start-by-pass" circuit, in order to have fuel while cranking the engine.

(the by-pass is not mandated, but will be useful if you were to have a fuel evaporated carburetor)

.
 
Last edited:
Thanks guys, for the information. I was wondering about the switch when starting, but your reply answered all questions.
 
Another method would be to place a Momentary switch at the helm.
This switch would activate the fuel pump prior to even turning the key to "Start".
IOW, no start by-pass circuit required....... sort of a primer system for when the boat has been sitting for a while!

Batteries and Starter Motors love this idea! :D

But in order to be legal, it must be a "momentary" only switch!

.
 
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