Mercontrol ignition switch of 1976 Mercury 650

[larrybowman]

Hi everyone, new to the forum, and new to boat repair, but experienced mechanic.

I have a '76 Mercury 650 with the Mercontrol that has the choke button above the ignition switch. Well, my rig is giving out on me. First the ignition switch refused to allow the motor to start. So, I figured out which wire came from the ignition switch to the switch box to kill the motor and just cut the wire and spliced into it to a toggle switch. So, that works ok, better than nothing. But, I really want to fix it, especially now that my choke button is giving me trouble.

So, last night I took the boat out and fired it up, but it was running super rich and would not idle. Figured out that the choke solenoid was still engaged. Had to disconnect the wire from the solenoid and then she ran fine. So, for now I have that hooked up on a switch in case it sticks again.

Anyway, I figured its time to fix the whole thing. I pulled the Mercontrol apart once and I know that the wiring for that switch is super tight in there and I don't relish the thought of replacing it. And, I see that most ignition switches have the push to choke feature, and cost half what my switch costs.

So, my question is this, could I just buy a newer push to choke Mercury ignition switch and get it to work without huge modifications? I figure, if it won't fit in the Mercontrol I'd just mount it beside the steering wheel and use it there. Probably prefer that anyways to trying to work with that tight wiring in the Mercontrol.

Has anyone done this and can give me some input on it? Maybe point me to an ignition switch that would work?

 

[Chris1956]

A push to choke ignition switch will work fine, provided it will fit into the Mercontrol. You could take the old ign switch and match it up to the new ign switch.

I would leave the old choke button installed, to keep the rain out.

OEM ignition switches are pretty tough. Are you sure it is bad? I just put all new wiring in my '77 MerControl. Wiring was down to a few bare strands, but the neutral switch, choke button and ign switch were fine.

 

[larrybowman]

Chris1956 Thanks for the response.

As for the OEM switch, I am pretty sure something in it went bad. But, I may be wrong.

What happened was I was on the water running full throttle and the motor just died like I shut the key off. Couldn't get it started for nothing. Had to be towed back. I got it home and checked everything I could think of, which is not much since I'm unfamiliar with outboard motors. I did some research and found that (I think) the blue wire on the switch box, if I disconnected it then the motor would start, but turning the key off did nothing, till I reconnected the wire to the switch box. Anyway, I ended up just splicing a toggle switch into that wire and that's how I've been running ever since.

Now, as far as i can tell, that wire I spliced the switch into comes directly from the ignition switch and is the one that is supposed to shut the motor off. So, I assumed that something in the ignition switch had shorted out to keep that wire on all the time.

However, I'm not too stubborn. If you think there is something else that is causing that to happen let me know and I'll check it out.

Back to the choke though, what would cause the choke to stay energized unless the choke button is sticking somehow? I mean, the physical button was not sticking, but seemed to be something inside there, or the ignition switch doing that.

 

[Chris1956]

The choke button is a solid copper dome (under the rubber), with a spring to keep it from making contact with another solid copper conductor.

They can stick closed, but are themselves very robust. I replaced one of those buttons (same kind is used) in my PTT, in 40 years.

I would wiggle the choke button and see if it will pop up.

 

[larrybowman]

well, then I'm not sure what happened. Because, when the choke was stuck energized the choke button still seemed fine as far as being able to press it, it was not physically stuck down that I could tell.

 

[jheron]

Could be the wire for the choke shorted out or there is corrosion in the switch that bridged the gap enough to keep the choke on. That old merc wiring is crap and should *all* be replaced.
Cheers,
Jon