1970 Model 500, 50HP, Trouble Stopping Motor

[Bandslak]

At present I have to shut the motor off by disconnecting the cable at the motor from the "MerCruser" control box and using a screwdriver to short out the motor. I have checked the cable and kill switch by connecting my multimeter to the cable and turning the switch on and off. This results in a beeping noise (in one position) which to me is indicating continunity in the cable. Also, I connected the multimeter to the two prongs on the engine where the above cable was disconnected from and it also indicates continunity. I gather the switch is meant to short out the motor (similar to what I have to do mannually) but does not seem to be working. Am I missing something here? Can anyone help me? Any info would be greatly appreciated, thanks..........

 

[new2mercs]

Re: 1970 Model 500, 50HP, Trouble Stopping Motor

I don't have an answer, though if the switch is supposed to short the magneto to ground I wouldn't expect to see continuity between the pins on the engine.

It sounds as though the switch is OK, and if it's killing when you short the connector pins on the motor that the internal wiring harness is OK. If these two points are true, I think all that's left is the connector itself. You might take a close look at the female (boat) side of the connector with a strong light and see whether there's corrosion on the mating surfaces.

 

[Bandslak]

Re: 1970 Model 500, 50HP, Trouble Stopping Motor

Thanks for the response.
I had another look at the cable today and it looks okay. I redid the continunity test (I guess it shows continunity because the multmeter is completing the circuit).
I have one of the "Seloc" manuals and I noticed today (I think I noticed it b4) that there was an extra wire comming off the switch box (blue connection) that was not shown on the wiring diagram. This extra wire leads to a condensor on the one side and is grounded to the block on the other. It appears to look like it belongs there but I am going to test the condensor shortly. Is it possible that this condensor is responsible for short circuiting the ignition so that the motor quits??
Something I did not mention initially was that the tach is a plug in at the front of the "MerControl" box and has not been working this year either. Possibly the condensor may power the tach (?).
Would you know what exactly is suppose to happen when you turn the switch on (or motor off, whichever)?