Merc 4.3 oil pressure switch

J

Jimmill

Cadet
Joined
Feb 12, 2009
Messages
17
I need to get a new oil pressure switch for my 2000 merc 4.3L - #OL646xxx. The engine would start and run for 30 secs to a minute and run out of gas. After a few try's it stopped starting and no gas at all to the carb, electric fuel pump would not come on until I bypassed the switch. Runs great with the jumper wire in place. The old switch has a 2 wire connection but the new switch's have 3? Anybody ran into this problem.
Thanks, Jim
 
cooter2506

cooter2506

Senior Chief Petty Officer
Joined
Apr 8, 2007
Messages
733
Re: Merc 4.3 oil pressure switch

Do you have an Audio warning system? Doesnt sound like you do. New switch will have three wires but still can be used in your application. One terminal will be common, one will be for the audio warning system(Normally closed or open on pressure rise) and the other will be for the fuel pump(normally open closed on pressure rise). If you have an ohm meter you can find which two terminals you need and just use those.
 
J

Jimmill

Cadet
Joined
Feb 12, 2009
Messages
17
Re: Merc 4.3 oil pressure switch

Yes, this engine has the audio system. I guess I'll just order the new switch and see if it will work.
Thanks, Jim
 
180shabah

180shabah

Rear Admiral
Joined
Mar 26, 2005
Messages
4,995
Re: Merc 4.3 oil pressure switch

It'll work, just use the common and normally open.
 
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