1987 gm 4.3 omc stringer mechanical shift

My 1987 GM 4.3L.OMC stringer with mechanical shift had been starting fine and out of nowhere, it has suddenly developed this problem. Sometimes when I turn the key it does not start, no click, nothing. If I monkey around with the shift cable at the engine where the neutral safety switch ( I think that is the name of it) I can sometimes get power to ignition again and it will start. This is an intermittent problem that is absolutely driving me crazy!! My battery is fully charged , I have removed and cleaned all the battery cables, ground and everything , the ignition switch is new but I tested it anyway and it tested good. I jumped the selinoid to ensure it and the starter were good and yes it got power and cranked over. I don't know how to test the shift interupter , electronic shift assist or neutral safety switch whatever it is called on this boat. Please throw in your 0.02 cents any help is appreciated.

sounds like the neutral switch in the shifter is faulty.
Could also be a faulty key switch at the helm.
Or bad start relay - not sure whether you were jumping the high current terminals or control side. If you jumped the control side and it started, then the relay is good.

hystat said:

sounds like the neutral switch in the shifter is faulty.
Could also be a faulty key switch at the helm.
Or bad start relay - not sure whether you were jumping the high current terminals or control side. If you jumped the control side and it started, then the relay is good.

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Thank you for answering my post...

I am not sure of the proper terminology for the connections on my starter selinoid but there are three. One huge red wire that goes to the battery (at 12:00 o'clock position), then another larger yellow and red wire, (3:00 o'clock position), and then a small purple wire ( 9 o'clock position). I jumped the 2 larger wires, red and yellow/red and the starter engages. I have tested my ignition switch (key at the helm ) a number of times both on and off the boat, and it has passed every test.

At times when this no start, no click problem happens, I go back to the remote box on the back of the engine. Where the throttle/shift cable runs and moves this remote box "armature', that controls the contacts on this "neutral safety switch".I adjust the knob on the cable and somestimes it will regain electrical power and start. Sometimes not. I think there is a very small part # stamped into the switch itself. I guess that would be needed to replace that switch.

What do you think? Is that what my step should be ?

neutral safety switch is inside your shifter. That switch on the linkage at the back has nothing to do with starting the engine.

your next step should be to google up a wiring diagram and find your start relay and test that, then test the neutral safety switch INSIDE your shifter.

hystat said:

neutral safety switch is inside your shifter. That switch on the linkage at the back has nothing to do with starting the engine.

your next step should be to google up a wiring diagram and find your start relay and test that, then test the neutral safety switch INSIDE your shifter.

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Will do. It will take me a couple of days but I will keep you posted.
Thank you

Debi said:

Will do. It will take me a couple of days but I will keep you posted.
Thank you

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Ok I am back after replacing the transom seal on this boat, I am resumimng my mission to correct the "no start" , "no click" problem I am having. Looking up the diagrams still. However, I have disasembled my throttle/ shifter to find three wires , one red/wht, green/wht and blue/wht. I noticed a small break in one of the wires. I am thinking this may be shorting out the neutral safety switch. I am back to work on it and I'll will be back with an update.