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Help Please! No Oil Pressure

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Chris Craft Johnny

New member
Was cruising yesterday at 3600 rpm's when Starboard engine just shut off! It was just like I turned the key off, no sputter or missing before shut down. No alarms or indication of any issues. Now when I crank the engine the pressure on the dash gauge does not begin to rise to complete the circuit to send spark to the ignition system. Does the guage on the dash get its signal from the oil pressure safety switch? I think it probably has it's own sender correct. I am really afraid I have an oil pump failure! Please give some advice as to how to check oil pump and pressure. I know I can bypass the safety switch to get the spark to the ignition, but I am afraid if the engine starts and the pump is not pumping oil I might do further damage.
 
Chris Craft Johnny said:
Now when I crank the engine the pressure on the dash gauge does not begin to rise to complete the circuit to send spark to the ignition system.
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I've never seen a stock marine engine kill the ignition if the oil pressure goes low. Gensets yes, prime movers no. I'd guess you sustained an ignition failure. Electronic ignitor very likely, followed by coil, followed by the distributor not turning any more. If you have a ballast resistor, maybe; but it should try to start even then as you crank.

Does the voltmeter on the panel indicate? Do you have electric fuel pump?
 
Let me expand on my comment "distributor not turning any more". Check that first. If your cam chain let go, the distributor won't turn, and you won't get oil pressure on cranking either. THe pump is fed by a coupler at the bottom end of the distrib
 
Diver Dave, I will be down in the engine room tomorrow. I will run the checks you suggested and some I could not run because of the heat in there yesterday. I will report my findings. Thanks for your suggestions.
 
Very possible that you don't see oil pressure just cranking her over. If the ignition is kaputt, that would explain it.

Jeff
 
which engine do you have?

There are a few different flavors of "oil pressure safety switches"....if you have a newer (mid-90's and later) style block, with an electric fuel pump, there is normally an oil pressure switch used there but it doesn't control the ignition. And the dash gauge gets its input from a sender unit, not a switch.
 
Correct. The oil pressure switch merely stops the fuel pump when no oil pressure is noticed--a USCG requirement.

Jeff
 
fastjeff said:
Correct. The oil pressure switch merely stops the fuel pump when no oil pressure is noticed--a USCG requirement.

Jeff
Click to expand...

I have been out of town for three weeks and have finally decided to tackle this problem. I have a somewhat newer Starboard engine than my Port. My Port has the Oil Pressure Switch on the Top Rear of the engine just in front of the Bell Housing. My Starboard, the one that won't start has what I think is a Sender and a seperate Switch on the Port Side (Left side looking from the rear of the engine) down low and to the rear of the engine. First, my Distributor is turning while I crank it using a hand held remote starter device. I am getting NO Spark out of the Coil while turning it over. I checked the coil with my Ohm Meter and when I put the leads on the Negative Terminal and one on the center I get 11,000. I read that between 6,000 and 15,000 was acceptable. Could it be the Oil Pressure Switch that has gone bad? Remember in my original post, I was running along fine xat 3400 rpm's and then it was like I turned the key, NOTHING! I installed a Pertronix Distributor in the boat about 2 years ago, could the Ignition Module or whatever you call it i the distributor have just quit working. I said I knew how to bypass the oil pressure switch, but that is on the older engine. What I think is the switch on the engine in question has only one wire coming from it. How can I test the system to find out if it is the oil pressure switch or the distributor? Can anyone post an illustration of these switches? By the way I do not have an electric fuel pump on this engine, it has the one with the bowl and small lever that goes in the block on the Front Starboard side of the engine and 13 volts on the gauge on my instrument panel. Thanks
 
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One issue per thread is a good rule of thumb...you can see the different oil pressure switches available by using the parts catalog link at the top of the forum pages...they are in the universal section. There are three major variations. First is the SPST NC type with a single terminal and the case making the electrical contacts. The other two have dedicated electrical connections - they don't use the case. One is a SPST NO type and the other is a SPDT, the later being used to simplify the wiring of the pump to the cranking circuit.
 
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