oil pressure switch question

I have an Ericson 30+ which recently had the heat exchanger replaced by a local boatyard. Since they did the work the alarm which used to sound when the ignition key was turned prior to start up has stopped sounding although the engine will start (The mechanic could offer no explanation).
The engine is a Westerbeke/Universal m3-20B. I checked the wires to the oil pressure switch and they seem ok. I am presuming the problem is the oil pressure switch which i intend to replace. My question is does the audible alarm sound directly from the alarm pressure switch itself (It seems a bit small for the sound to come from that!) OR is there a separate sound annunciator/sounder somewhere that I should also check?
Thanks,
Mike

HI Mike,

On our E30+ the overheat and the oil alarm each have a sending unit on the engine, with the wires leading to an alarm buzzer located behind the engine panel in the locker. I wonder if the mechanic might have dislodged the wire from the sending unit while working on the engine on your boat.
Just a thought....
Frank

What is your engine? Mine is a circa 1982 1GM. When I bought the boat, the gauges didn't work. I wiggled a bunch of the wires and traced them back and now they do... Who knows, maybe it is gremlins with these old boats. I can send you the wiring diagrams if you have a yanmar 1/2/3 GM. Lemme know.

Mike,

My 30+ has the Universal M18. It's almost identical to your engine but has 1/3 fewer cylinders. The alarm is definitely distinct from the switch. I just replaced both of mine. Our engines have the same Universal Service Manual. (Let me know if you need it.) On page 55, there's a diagram.

I no longer have a warning light but I have an alarm.

Hope this helps,

Jim
Woolamaloo
1985 E30+ Hull #685

Oil Pressure switch

Mike, does your 30+ have an oil pressure guage? If it is working properly, I would check the connections to the alarm/buzzer unit.
Harold, Mischief Maker

Mine has the buzzer light on the panel, I replaced it last year. I had a little trouble getting it to work after replacement, make sure you have a good ground. It's most likely a bad connection behind the panel. On my M25 it is unrelated to the heat exchanger.

Thanks

Thanks for all your responses.
The oil pressure gauge reads ok. I did find the audible annunciator located behind the Admiral control panel and checked the connections to that. I also cleaned the terminals in the oil pressure switch and the sender but still no luck. The wiring loom looks ok and all other wiring looks fine but there are a lot of wires. It seems a big coincidence that the switch would go bad while he was working on it so i will continue wiggling wires for a while before i buy a new switch!
Thanks again for all input.
Cheers!
Mike