New Oil Press Gauge=NO START?

[GaJeff]

Hi all... I have an 81 Citation 19ft. With 120Mercruiser 4cyl. Alpha1 outdrive. Just installed a manual oil pressure gauge on the engine. Now it won't start. It will catch for just a sec and die before it kicks up. The old gauge had an electric sending unit screwed into the side of the block with a blue or purple wire on it. I took it off and installed a 1/4" compression fitting on it and ran a line from it to the gauge. Hooked up my ground and light. The other gauge is fully electric with ground, pos, and a sender wire going to it. The wire at the sender goes into a harness and up to the dash.


Is it possible that with no signal from the sending unit the engine will not run? Can I bypass this to run my manual gauge? Or is changing out the gauges no problem and I have some other issue? I have ran the boat everyday this week and no problems at all. So I know it runs but maybe something else has happened.

Any help is appreciated in advance
Jeff

 

[nola mike]

Re: New Oil Press Gauge=NO START?

I'm having a hard time picturing your wiring, but if you removed a purple wire it's possible that you disconnected a 12v lead that would ultimately go to your coil. Check voltage at the coil in the run position.

 

[GaJeff]

Re: New Oil Press Gauge=NO START?

Well as it turns out removing the oil pressure sending unit it somehow tied to the ignition. Looking at the wiring diagram it's not but some hack job tied it in. I guess it's a good engine protection circuit but it limits me to installing a manual gauge. I just got a "T" fitting and running both gauges for now. I'm going out today so I'll figure it out throughout the week.

 

[Bt Doctur]

Re: New Oil Press Gauge=NO START?

the oil pressure sending unit has nothing to do with ign.maybe you looking at a no oil pressure type switch in the ign circuit.