need help to id a part on a 77 500 merc

[greasemonkeyjmj]

ok ill do my best to describe it. it fits on the starboard side of the front support bracket, the bracket in front of my carbs that the top and bottom cowling fasten to.it is up above my start solenoid. the part is light blue and kinda shaped like a condensor or a resistor of some type, it has 2 wires running from it, and is wired into my kill switch circuit. any ideas what it is? and the proper part name for it ? i am wanting to change it due to the fact that the wires are suffering from the old merc harness rot ....LOL

thanks

 

[emckelvy]

Re: need help to id a part on a 77 500 merc

This is called, ironically a "mercury" kill switch!

Mainly because it's filled with mercury and acts to kill the ign when the motor is tilted up. The mercury flows to bridge the electrical circuit within the switch and grounds the ign circuit.

You can look the part # up here, just find the serial # group for your motor and pull up the dwg showing the switch:

http://www.mercruiserparts.com/SelectModelType3.asp?class_id=2

HTH........ed

 

[greasemonkeyjmj]

Re: need help to id a part on a 77 500 merc

thanks for the info on this. is the mercury switch something that is a must have ? or can it be wired around ? and the motor still run

 

[emckelvy]

Re: need help to id a part on a 77 500 merc

James, the motor will run just fine without it.

What I didn't mention is that the primary purpose of killing the ign when tilted is for underway operation; if you should happen to hit a submerged object, and the motor flips up. Stops the motor right away.

Of course disabling a safety feature is done entirely at your own risk. But it won't affect normal operation of the motor except for loss of that feature.

HTH.......ed

 

[achris]

Re: need help to id a part on a 77 500 merc

Part # -58124A20

 

[greasemonkeyjmj]

Re: need help to id a part on a 77 500 merc

thanks fellows

 

[rapalaman1963]

Re: need help to id a part on a 77 500 merc

Hey guys I was looking for this same part! On mine the wire has broken off will this make a difference on how the motor runs?