OMC remote controls with the big red plug…

[johnyrude200]

Is it common for the stop circuit to fail on these control boxes? This is yet another area I am just delving into, and I am finding a slew of control boxes where either the stop circuit fails (no spark) or when I start a motor and turn the key to the off position, the motor isn’t being shut off.

I’ll be taking a look at my wiring schematics shortly, but figured I’d ask the panel.

Thanks

[beerman57]

Sounds like ignition switch, unplug the big, red plug and jump the solenoid to check for spark. Have the plugs out so it can’t start.

[johnyrude200]

I’m going through the service manual, and have already confirmed 1 out of 3 faulty remote control boxes I have has a faulty stop circuit. I suspect all the other issues I’m finding are related to similar issues with the control boxes (they are all used).

I am just starting out with the use of control boxes with key switches, and I know they aren’t too complicated, but was just wondering if it’s fairly common for the stop circuits to go on these things.

Can these be repaired – or are they replacement type situations. The service manuals don’t really explain how to fix them, just how to find the problem.

[johnyrude200]

OK, now I’m stumped. I tested a control box and it passed all of the functional tests of the service manual, yet the motor will still not shut off when I turn the key to the off position.

I tested the powerpack with a continuity meter and connected to the black/yellow wire from the powerpack and the other meter lead to the ground, and it shows continuity (a little bit of resistance).

I used a known bad powerpack with a faulty stop circuit, and running the same procedure, it showed no continuity between the powerpack ground lead and kill switch lead (black/yellow).

What am I missing here?

[Casey Lynn]

Assuming the control boxes are the side mount variety?
If so, there is supposed to be a piece of heavy stiff plastic between the control box case and the key switch. This was added due to the extremely tight tolerances in that area. Check to make sure that is in place. If not there is a good chance the black/yellow may be grounding through the control box case half.
Second, if someone has changed out a key switch the routing of the key switch harness can be quite a task to get right. Check for areas on the black/yellow wire sheathing that may be rubbed through.
If this has a very early key switch (without the raised black/yellow terminal) there is a chance of carbon tracking to ground. Check it.
As far as not shutting off……When the key switch is turned to the off position the black/yellow is connected to the black wire (ground) so check the terminals on the back of the key switch to make sure this is happening. If not, it is your key switch. If it is then ohm out the harness and see if there are opens in either of those two wires.
Also, check to make sure the wires are on the correct terminals on the back of the switch. Your manual will lay that out for you.
This will either confirm or eliminate the control box/harness.

[johnyrude200]

I’ll give that a try, great advice. I know the motor is fine, I’ve been running it all day calibrating/bench testing it. I was just planning on connecting up the control box to verify that was OK before installing on my boat, but I have apparently run into yet another snag. The motor (35hp 1978 Johnson) does not have a kill switch, so for the past week of me working on it, I’ve just been using the choke to kill it off. Obviously once mounted on a boat, I need a safer way of shutting the motor down, god forbid we ever hit something…I want that kill lanyard functioning properly.

It is the side mount control box, but I am hoping to install the binnacle (vertical) control box, I would assume the wiring is all the same, just a different cosmetic configuration?

[fleetwin]

Well, with the addition of the emergency safety lanyard switch in the early 80s, reliability started to decline. Those safety switches can be very sensitive and the lanyards are prone to wear which might not be depressing the safety switch far enough.
I am confused about just what you are testing with the ohm meter, there are no specs for testing the powerpack black yellow lead and ground. You should be testing between the control box harness pins between the black/yellow and black leads. You will need a service manual to spell out which pin corresponds to which lead. But, and this is important, just because the ohm meter might read infinity between these two leads with the key "on" does not guarantee there is no stop circuit problem in the control box harness/key switch/emergency stop switch. Needless to say, there IS a problem if the meter leads less than infinity on the high ohms scale. Keep in mind that there might be a problem in the engine harness as well.
Papster mentioned some good areas to look at, look for spliced/taped leads as well, good places for arcing. Some larger rigs use a harness extension, sometimes salt water gets into the red plug connectors hidden in the boat. I’m assuming the rigs you are working on are not long enough to require and extension though. You can usually see black arcing marks inside the red connectors if problems have occurred there.
All that being said, the reliability of the control box wiring/key switch/emergency stop switch is pretty good. Needless to say, exposure to salt water certainly creates a nice path for arcing, the key switch and emergency stop switches should always be replaced if the boat sinks in salt water, but I guess that is the least of the problems after such an event.

[johnyrude200]

I used the service manual to test the control box harness (red plug) and it passed all of the functionality tests. Yet, when I turn the motor on and have it running, when I turn the key switch to OFF or press the kill switch, the motor still runs. I had 2 other control boxes which just plain aren’t working right (I’ll get to those at a later date).

I may have just answered my own question, but I started testing the kill circuit on the motor end to see if there is a break in the black and black/yellow wiring somewhere which is preventing the ignition from grounding out to kill off the motor. I suspect there is a disconnect somewhere in that stop circuit on the motor side which is why the control box has no way of killing off the motor in the off position or with the stop switch with lanyard.

Granted, it’s been a long day of labor, and I think my focus was probably getting foggy, so I called it quits for the night and will get back to it first thing next week (heading out on my other boat in boston harbor and then up to portsmouth NH this weekend…yippee and nice weather to boot!)

[fleetwin]

Oh, so the problem is the engine won’t shut off! I guess I would start by checking the resistance between the black yellow lead and ground right at the engine side of the powerpack three pin connector with the key off. If this test fails, you could check resistance between the ground and stop pins on the control box side of the red plug with the key switch off. You could also check the engine side of the harness making sure the ground pin of the red plug is actually grounded and there is continuity between the stop pin in the plug and the black yellow amphenol pin at the harness side of the pack connector.
Keep in mind that the pack itself might be at fault as well, although there is no published resistance test for this. But again, none of these issues are very common problems.

[billw]

For the record, I have seen the harnesses go bad for the stop circuit, either the control box harness or the engine harness. In all the cases I have seen, which is maybe 10 times, there is a failure between the wire in the harness and the pin in the harness. In all cases, I was able to peel the insulation back from the plug a few inches and jump across the plug with an additional bullet connection. Of course, you have to troubleshoot and find exactly where YOUR problem is. All I am saying here is that I have definitely seen the problem in harnesses.

Long live American manufacturing!

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