1993 Mercruiser 5.7L

[DockDepot]

I am working on a 1993 Mercruiser 5.7L. The problem I am having is that when I turn the key on without cranking the alarm goes off. When I start the engine the alarm stays on and never goes off. And when I start it right up the alarm goes off. I have checked the gear lube and it was good and when I start the engine the oil psi on the gauge reads around 40 Psi cold. The engine runs properly with no running problems. Battery voltage is 12.37. Thanks for all the input!


Jon

 

[Bt Doctur]

The alarm activates by grounding the wire on the drive res bottle, the oil pressure switch and the over temp switch. With key on and motor not running the alarm will sound from 0 oil pressure, thats normal

 

[DockDepot]

Sorry I didn't add this in but the alarm stays on even with the engine running.

 

[DockDepot]

And this engine does not have a gear lube res.

 

[Bt Doctur]

The wire is a Tan/blue stripe wire
remove the wire from the water temp switch to see if it stops the alarm
remove the wire from the no oil pressure switch to see if it stops the alarm
Yes to either is a bad switch

 

[DockDepot]

I have found the water temp wire but I am having trouble finding the oil pressure wire. Where on the engine is it located?

 

[kghost]

typically near the oil filter but if not near tha back of intake manifold to the right of the distributor. Follow the tan with blue stripe wires.....

 

[DockDepot]

Thank guys for helping me out. I traced the Tan/Blue wire behind the engine and it led me to the gear lube reservoir on the transom completely out of site. The lube was low and causing the alarm, I thank all of you again for your help.

 

[Bt Doctur]

Now you need to find out why it was low. Simply adding more oil may lead to drive failure down the road