1975 Mercury 850 85 hp Thunderbolt

[skneblett]

I have a 1975 Mercury 850 85 hp Thunderbolt and redoing the wiring. I had to buy an after market ignition switch (marpac order no. 7-1150). I have looked at all wiring diagrams possible and can not figure out the choke wire due to difference in the wire color. Can any one help. Thanks!

 

[Barnacle_Bill]

Re: 1975 Mercury 850 85 hp Thunderbolt

There should be a position marked "C" on the switch. The gray wire from the motor goes there for the choke to work.

 

[merc850]

Re: 1975 Mercury 850 85 hp Thunderbolt

I have an 850 too and the choke is a button on top of the MerControl
box, here's the wiring diagram.

 

[skneblett]

Re: 1975 Mercury 850 85 hp Thunderbolt

I have an 850 too and the choke is a button on top of the MerControl
box, here's the wiring diagram.
View attachment 96919

Thanks! I got the wiring figured out.