Choke problems on a '76 115

[Nightfisher-]

I'm having problems with a 76 Johnson choke solenoid. The motor ran great untill I had a short in the hot wire coming off the rectifier. Replaced the rectifier and the motor would crank, but blow the 20A fuse as soon as I bumped the choke switch. The choke solenoid was badly rusted and seemed to move freely, but I decided to replace it just to be on the safe side. $138 for that lil booger. Wow! Motor ran fine on the next trip out, no problems whatsoever. Next trip the boat cranks, but will not start. Smells like it's flooded so we pulled the cover off to take a look and let it air out. That's when we noticed the plunger in the new choke solenoid was stuck in the down position and would only come up with assistance from pliers. It was also very warm, almost too hot to touch at first. The inner sleeve was apparently bulged by the heat and wedged the plunger. $138 down the drain. I removed it and attached a manual chake cable to the post the plunger was attached to. All I have to do now is pull the manual choke start the motor, then push the manual choke closed. Works fine to me, but I was just wondering two things.

1. Is is harmful to the motor to use this manual arrangement?
2. What could have caused the brand new choke solenoid to overheat like that? I made sure my ground and purple wires were connected cleanly and correctly when I installed it. I'm damn sure not spending another $138 for another new one if I can't figure out why the first one burned up. I'll just stick with the manual choke if it's not doing any harm.

 

[Joe Reeves]

Re: Choke problems on a '76 115

The manual choke does no harm.

Either the "C" (choke) terminal of the ignition switch has 12 volts being applied to it constantly somehow OR........................

(Temperature Actuated Choke Solenoid Conversion)
(J. Reeves)

Various OMC engines that were manufactured in the later 1960s thru the early 1970s, for example the 1969 55hp Evinrude/Johnson incorporated a dual stage choke solenoid...... easy to identify as they have two wires leading to the solenoid, one purple/white, one purple/yellow.

The purple/yellow is attached at the engine wiring terminal strip to another purple/yellow wire that led to a heat sensor. The initial stage, with the key ON, (purple/yellow), when cold, would keep the choke pulled in half way until the engine warmed up, at which time it would release and open the choke butterfly.

The second stage (purple/white) is attached to another purple/white wire at the engine terminal strip which leads to the choke switch. When the switch was engaged, the choke closed etc.

The problem with this setup is that as the engine got older, the thermostat acted up, water pump became weak, whatever, the heat sensor failed to operate properly and the choke would not release from that half closed position. This would cause the engine to run in a rich fuel mixture condition (flooding, loading up).

The cure to this problem, via a service bulletin from OMC was to remove the solenoid purple/yellow wire from its original location and connect both of the solenoid wires (purple/yellow & purple/white) to the engine wiring harness purple/white wire at the engine terminal strip.

The above change would allow both solenoid wires to be energized when the choke switch is engaged, pulling the choke butterfly in firmly..... and only when the choke switch is engaged.

 

[bktheking]

Re: Choke problems on a '76 115

Did you test the solenoid besides changing it cause it looks rusted? Just by what you are saying, doesn't sound like the issue at all. Sounds more like a shorted ignition switch rather than a solenoid issue. Blowing fuses and burning out brand new parts is a symptom, not a cause. If I were you i'd find out what it REALLY is, if it's a push to choke setup chances are it's a wiring/switch issue. Exchange the dead solenoid for a new one if you can.

 

[Nightfisher-]

Re: Choke problems on a '76 115

Ok, so what it says is to hook both the purple/white and purple/yellow to the purple/white terminal together instead of separate terminals as they now are? (Or were before I disconnected it) I guess this means I should check the thermostat and water pump as well. The pump and impeller were already on my to do list anyways although the motor does seem to spit pretty good. I've only had this motor about 2 weeks. Had a '98 Merc 40hp on the pontoon I used to have. It was WAY different than this one. lol.

 

[Joe Reeves]

Re: Choke problems on a '76 115

A first portion of your question states "Ok, so what it says is to hook both the purple/white and purple/yellow to the purple/white terminal together instead of separate terminals?"

Yes...... this enables voltage to be applied to the choke solenoid when the choke switch is engaged and ONLY when the choke switch is engaged.

 

[Nightfisher-]

Re: Choke problems on a '76 115

Did you test the solenoid besides changing it cause it looks rusted?

I did not test it. We did hook it back up briefly after the new one took a dump, and it went right back to blowing the fuse when the choke switch is engaged. That's when i made the decision to bypass it completely. Funds for boat repairs are depleted now and I'm not likely to be able to spend more than a few bucks at a time for any further repairs. Hopefully there will be no more costly repairs or mistakes that pop up.

 

[Nightfisher-]

Re: Choke problems on a '76 115

Gotcha Joe. If I decide to hook it back up in the future I will rewire it from the switch back and hook it up like that. Great responses BTW. You guys were all over that one. Thanks for the tips and advice. Keep 'em coming if anyone else has any ideas.

 

[bktheking]

Re: Choke problems on a '76 115

If it kept popping fuses then it was likely shorted. JR probably nailed it on the head. Fix the issue and exchange the part as defective. I guess a half closed choke on all the time would do it, they are only meant to be used for on for 5 second of more.