Mercury 650 ignition issues--UPDATE

golfrbob2

Recruit
Joined
Jul 21, 2008
Messages
5
I have a 1968 Mercury 650. I can get the boat to start by using the battery and jump starting the starter with jumper cables, bypassing the solenoid and the ignition key. Boat will start and run.

However, when I try to use the key, the starter does not turn over. I bought a new solenoid and replaced that. I have tested it in the following ways:

I put the positive of the voltmeter onto the positive of the solenoid. When I turn the key, I get 12 volts. However, this is with the grounded side of the solenoid not hooked up and the negative side of the voltmeter connected to the negative on the actual starter. However, when I connect the grounded side of the voltmeter to the grounded side of the solenoid while it is grounded, I get no responseat all . I hhave to ground the voltmeter to a separate ground, which I find odd. Otherwise, when I turned the key, I do get 12 volts. I don't get anything coming out of the yellow starter cable however.

It is almost like the ground side of the solenoid is not working properly to allow the solenoid to open. Using alligator clips I have tried grounding it to everything on the engine and when I connect the negative on the voltmeter to the negative on the solenoid or on the alligator clip where I have grounded the solenoid, I don't get any voltage.

UPDATE:

When I connect the solenoid ground to the battery ground, the solenoid will open, but the starter did not turn over. Then I connected the starter ground to the battery ground and it fired up with the key.

Any ideas why I can't get these two cables to ground out? I have tried connecting them to every part of the engine cowling.
 
Last edited:

Barnacle_Bill

Admiral
Joined
Feb 8, 2004
Messages
6,469
Re: Mercury 650 ignition issues--UPDATE

The cowling is not a ground. You must use the engine block. If it still doesn't work, temporally run a jumper cable from the NEGATIVE post of the battery to bare metal on the block. You may have a bad ground cable.
 
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