mercury switch

[ouchita]

what is the purpose of the mercury switch. My book doesnt tell anything about it just shows it in the wiring diagram. I have a 1976 mrecury 850 and i found the mercury switch with a wire broke on it. The motor also will not stay running while in gear wondering if this could be the cause

 

[sschefer]

Re: mercury switch

what is the purpose of the mercury switch. My book doesnt tell anything about it just shows it in the wiring diagram. I have a 1976 mrecury 850 and i found the mercury switch with a wire broke on it. The motor also will not stay running while in gear wondering if this could be the cause

The mercury switch is a normally open switch. If you hit something hard and the motor kicks up the switch closes and grounds the ignition temporially cutting off the engine so it does not over rev and blow.

There will be a black and yellow wire connected to one end of the switch that terminates at the switchbox. The wire on the other end of the switch terminates at ground. If the black and yellow striped wire is bare and intermittently touches ground it will kill the engine. If the other wire is disconnected the mercury switch will not work.

 

[ouchita]

Re: mercury switch

Thanks for the information. I was hoping that was why the motor would not stay running while in gear guess not

 

[ouchita]

Re: mercury switch

Anyone know where I can find a new mercury switch. Ive searched everywere on the internet and cant find one.

 

[sawblade723]

Re: mercury switch

My engine would go dead while running WOT and would not restart for about 30 minutes. Then it would crank and run again for a while then just die. My mechanic removed the mercury switch and taped up the wires and I have had no more problems.