1977 mercury 850 finally got spark now what?

[Dacanadian]

Hi, I inherited my grandfather's late seventies vanguard boat, with a '77 mercury 850. Boat needs some tlc since it sat for at least five years. Anyway I've been trying to get it going, had no spark. Figured out that I needed a new switch box. Replaced that and still had no spark until, I removed the orange wire from left side of switch box. Lol I don't really know what I'm doing but I know that I shouldn't start it until I figure out that wire situation. What's next? Would it be the ignition switch. Hopefully I can figure it out by July long weekend. Lol marrettes are temporary. :faint2:

 

[Chris1956]

Re: 1977 mercury 850 finally got spark now what?

orange wire is killer wire. It is grounded to kill the ignition. So, find out where it is grounded (hint Ignition switch) and see why. It could be something as simple as a bad ign switch.

Also check mercury switch on the port side of the motor, above the switchbox. It can ground out the ign as well.

 

[Dacanadian]

Re: 1977 mercury 850 finally got spark now what?

Like I say I'm no mechanic. I tested ignition with test light and put clamp on ground wire and light probe to orange. Didn't get light. So it's got to be in the ignition? I did this with key off. Should light up if off. Did the same thing with key on and start position just to make sure.

 

[Chris1956]

Re: 1977 mercury 850 finally got spark now what?

Well the orange wire appears to be grounded, somewhere. Pull the quick disconnect and then test it for ground. If the ground is gone, at least you know the problem is in the boat.

 

[Dacanadian]

Re: 1977 mercury 850 finally got spark now what?

Lol it's in the boat!

 

[turtles11756]

Re: 1977 mercury 850 finally got spark now what?

maxrules.com has the wiring diagram go over all the wiring from the key switch to the motor .and while your at it look over all the fuel lines too

 

[Dacanadian]

Re: 1977 mercury 850 finally got spark now what?

Hooked up quick connect checked continuity from the engine to key ignition on the kill wire, it was good. So went out to and bought a new ignition hooked it up and no problems now. Had it out yesterday and found out that you have to have the motor all the down to start. I'm thinking that's because the mercury tilt switch? Thanks for the help guys!

 

[Yesterday]

Re: 1977 mercury 850 finally got spark now what?

Yes that's the tilt switch's function. I disconnected mine.

Nice looking boat!