Fuel pump oil pressure switch - engine dies

[utexasrick]

Cant seem to figure out this problem, here the history. I've got a 2006 mobius, 5.7 carb, I was having problems with the engine dying when the boat was idling right after I would start it. The issue is with the oil pressure switch on top of the engine near the distrubutor. The oil pressure on the dash gauge reads about 40 psi at idle (not sure how accurate that is) at around 700 rpms. When I jumpered out the switch and just connected all the wires the boat idles fine very smooth slightly high though around 800-900 rpms. So I figured the switch was bad. I bough a new one of skidim, installed and still the same problem. The engine idles for a few seconds then slowly dies. From what I read, two of the wires for the switch provide power to the fuel pump when cranking, then the other is constant once the switch closes. I verified the fuel pump has power when cranking with just the two wires together and that the other one also has constant power. Could the oil pump be going bad and at low speed? provides very little pressure? this would mean that the dash gauge is incorrect.
My next test will be to plug in an oil pressure gauge to the port where the switch is located and see what the actual pressure is at that location just need to go buy one.
Not sure if this is also related but after driving the boat around for a while then anchoring for a while the first time trying to start it again it dies very quickly, even with the switch jumpered, I have to prime the engine by giving it a few throttle pulls, then start it. This seems unrelated though maybe need to clean the carb

[parrothd]

Cant seem to figure out this problem, here the history. I've got a 2006 mobius, 5.7 carb, I was having problems with the engine dying when the boat was idling right after I would start it. The issue is with the oil pressure switch on top of the engine near the distrubutor. The oil pressure on the dash gauge reads about 40 psi at idle (not sure how accurate that is) at around 700 rpms. When I jumpered out the switch and just connected all the wires the boat idles fine very smooth slightly high though around 800-900 rpms. So I figured the switch was bad. I bough a new one of skidim, installed and still the same problem. The engine idles for a few seconds then slowly dies. From what I read, two of the wires for the switch provide power to the fuel pump when cranking, then the other is constant once the switch closes. I verified the fuel pump has power when cranking with just the two wires together and that the other one also has constant power. Could the oil pump be going bad and at low speed? provides very little pressure? this would mean that the dash gauge is incorrect.
My next test will be to plug in an oil pressure gauge to the port where the switch is located and see what the actual pressure is at that location just need to go buy one.
Not sure if this is also related but after driving the boat around for a while then anchoring for a while the first time trying to start it again it dies very quickly, even with the switch jumpered, I have to prime the engine by giving it a few throttle pulls, then start it. This seems unrelated though maybe need to clean the carb


Priming with the throttle always helps starting a carb boat, its why I never turn my boat off.

I would start with a tune up, fuel filter, cap wires, rotor and plugs. I'd also check the wiring on the choke and make sure it fully opens.

[utexasrick]

well found out I have the wrong oil pressure switch, the new switch that I bought from skidim was for the trans, apparently its always closed then it opens with pressure. Couldn't find the right one on their site though. Anyone have any luck with oil pressure switches from auto parts store?

[1cabinman]

Did the correct oil pressure switch correct your issues??? Did you have a 3 prong switch and replaced with a 3 prong (connector) switch?

[Stazi]

well found out I have the wrong oil pressure switch, the new switch that I bought from skidim was for the trans, apparently its always closed then it opens with pressure. Couldn't find the right one on their site though. Anyone have any luck with oil pressure switches from auto parts store?

I bought one from my local NAPA, years ago.


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