Had a similar problem this summer.We didn't quite figure it out then, but a little later.

Dunno what engine you gots, but the oil pressure loss in my Ford was due to 2 lifters popped from the bores. The problem that caused THAT was hydrolocking (2 extremely bent pushrods, 2 jacked up roller rockers).

My running it anyways, thinking it was the guage, spun 4 rod bearings and pretty much ruined the engine. Time to tear it down, in other words.............

Ray

Double check the wiring behind the dash before tearing into the engine.  Most of the time you will find a poor connection, but sometimes you will find mass destruction inside the engine 

i hope its something simple.. i had it out at havasu a few months ago and she ran great.. and when i started it up she still sounded good... nothing had really changed....

Cant you just ground the sending unit to the block? If the guage jumps all the way up you can confirm that the sending unit and gauge is working....if the guage doesnt move you can verify that something isnt working....

NO!

No you can't, that is the easy way out and we will have none of that!!   




Yes, this is the best idea yet...

Jumper the terminal on the sending unit to ground and turn on the key, gauge should go passed the 100% mark. Then you can eliminate the gauge, then get a mechanical gauge (used works best  ) and see if the engine is making any oil pressure. If not, that sucks, if so....sweet! your only out a sending unit...

Seeing as I have had dozens of boats apart in the last 20 years, I'm betting on a wiring issue or a bad gauge...

GT

sounds like a plan

had a similar problem on the rogers except it would peg the needle way past 80 and we didnt have great oil pressure bc the pump was shot(Brand new pump) put in a new gauge and saw the incredibly low oil pressure... 

Ya, I just bought my Crusader a few months ago. The prior owner had an automobile sender to a marine guage so the Ohms were different. I put a marine sender on it and now the oil guage works properly.