Mercruiser 3.0 starter click no start

B737driver

Recruit
Joined
Oct 29, 2019
Messages
3
First off... I have searched and read multiple threads dealing with this issue but I still have a question.

When I attempt to start I get the slight click in the engine compartment. Because the engine is in the center pontoon there is not enough access to determine exactly where the click is coming from....and the boat is in a slip on the water currently. I replaced the slave solenoid a few months back and this seemed to fix the issue. I haven't taken the boat out in a month or so and today I show up and there it is again...click, no starter engagement.

I tried jumping the battery...click. I then jumped (hot-wired) between the two large terminals on the slave solenoid and the starter engaged immediately and the engine fired right up.

If I had a ground issue would I get a click or nothing, and would jumping between the terminals work?

Seems to me as though the slave solenoid has gone out once again but that seems really suspicious. :confused:

Any help or direction would be appreciated. Thanks
 

Reserector_

Petty Officer 1st Class
Joined
Oct 15, 2019
Messages
267
When you jump the terminals and it cranks, I would have to say that your ground connections are likely OK.
That solenoid is an electromagnet that slams a heavy contact closed. At the same time, it shoves the pinion gear out to engage the ring gear on the flywheel. I can think of a few potential failure modes for that solenoid:
Faulty connection where the battery cable bolts to the solenoid - not delivering enough voltage/current to get the job done.
Not enough voltage reaching the trigger wire (from the key/relay) on the solenoid. Dirty or loose connection, perhaps.
Arced-out contact (internally). Not very likely if it was recently replaced.
Mechanical drag in the mechanism preventing the solenoid from moving easily, requiring more current, i.e. another battery and jumper cables.
 

B737driver

Recruit
Joined
Oct 29, 2019
Messages
3
Thanks for the assessment. I'm pulling the boat out if the water soon. Then I'll start tracing wires and checking voltage. The key to solenoid wire voltage seems to be the likely culprit.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
23,762
So you jumpered the secondary (large) terminals on the slave solenoid, and she started? That implies that slave solenoid is not working, however, since you just replaced it, i would suspect the ground and /or power to the slave solenoid primary coil.
 

Reserector_

Petty Officer 1st Class
Joined
Oct 15, 2019
Messages
267
I think I misunderstood your original post. I thought you were describing the solenoid on the starter itself.

Sounds like you are on the right track in spite of my misguidance.
 

B737driver

Recruit
Joined
Oct 29, 2019
Messages
3
Finally got around to fixing this. I followed the guidance in the link above...and it was the slave solenoid again. I replaced it and all is good for now. thanks for the help. Hopefully this one lasts longer than a couple of months.
 

Fed

Commander
Joined
Apr 1, 2010
Messages
2,441
Was the first replacement solenoid a genuine mercruiser one or an aftermarket / car solenoid?
 
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