Intermittent alarm from oil pressure switch

[jesse_boston]

Ahoy. Sorry for all the multiple threads, don't really want to mix up topics and this boat definitely had it's fair share of issues.

I narrowed down the intermittent alarm I'm getting to the oil pressure switch.
On my boat (1995 Doral 230, Alpha 1 Gen 2 5.7 carb), the sender for the oil pressure gauge is in the head, and it reads around 40-50PSI at idle, 65 or so if I throttle up. I've never had the engine at WOT, so I don't know whether it would continue to climb.
If I rev up just off idle, 800 RPMs or so, the alarm goes off. I narrowed it down to the oil pressure switch, which is in the block next to the oil filter.
Can anyone think of a reason why I'd have 45PSI in the top end and less than 6PSI in the block at the pressure switch?
I don't want to kill the engine, and the family wants to take out the boat this weekend.

I want to believe it is just a bad switch. I'm going to order up a new one, but they don't exactly carry them at O'Reilly's... or do they? Can I use any standard GM part?

 

[Bondo]

I want to believe it is just a bad switch.

Ayuh,....... With the oil pressure it's showin', I agree,.....

Pull the alarm wire off it,..... if it can't ground the buzzer, it won't buzz,.....

 

[jesse_boston]

Good to hear. Seems that Napa (and west marine) used to carry the Sierra switch but don't stock them anymore.
I'll leave the wire off and watch the gauge and try to have a good day on the water
Here's from last night:

 

[alldodge]

Can anyone think of a reason why I'd have 45PSI in the top end and less than 6PSI in the block at the pressure switch?

You don't have low pressure, its a bad switch

Yes, get it from the GM dealer, just take it with you and they can find it. Or go to a NAPA and they can find it.

I found some just looking for GM oil pressure switch like at summit racing. Can find looking for oil pressure light switch

All that said, so long as your gauge is not showing an inaccurate reading

 

[jesse_boston]

alldodge good point about possibly inaccurate gauge reading. I don't trust anything else on this boat, why should I trust that?

I went over to an auto parts store, nothing quite matched up with the threaded stud wire connection that merc put in this year series.
Oil pressure light switch for a 1987-1994 Honda Accord (PS198) is the right thread, has a round stud connection (non-threaded), and has a cutoff of between 6 and 10 PSI (haven't found an accurate spec). This'll do so I know I'm not trashing the engine.