My 90hp Mercury starter won’t quit turning ???

[chucker]

My 90hp Mercury starter won’t quit turning over with the key in the off position? I had to disconnect the battery cable to get it to stop, if I hook the battery cable back up it starts turning over. I figure this ether has to be the starter solenoid or the ignition switch I’m leaning towards the ignition switch.

Does anybody have any thoughts on this?? Also I need the boat for this weekend if any one has a method to jury-rig it to work if I can’t get it figured out tonight.

Thanks in advance for any suggestions.

Chucker

[musky hunter]

You are right on track with you're diagnosis. It is easier to work on the solenoid than the ignition switch, you've got a 50/50 chance. Unbolt the starter, swing it out of the way of the flywheel, and retighten for testing if you can. This way you can touch and remove the starter wire to determine if the solenoid is functioning without damaging the bendix gear or flywheel. You can try lubricating the plunger of the solenoid, it's nothing more than a coil that pulls in two contacts. If you have an electrical tester, you can test for continuity from the ignition wire to ground. If there is continuity, and it doesn't change when you work the switch, then it's the switch. A friend of mine had a similar problem and needed to jury rig the switch. It's relatively simple to do, you can get wire, a switch, and connectors at the auto parts store. However, you need to know that the kill function on you're key still works. But you just bypass the ignition wire and bring a hot to the starter terminal through the switch. You want a momentary switch if you do this. The safety considerations to consider are loose wires that might arc and potentially cause a fire, particularly near gas. So if you do jury rig, make sure you're wire is well protected and the temporary switch well secured to the boat. And any loose wires, like the ignition wire, is well capped so it can't cause a short.

[Valv]

You might try to tap the solenoid a little, if it's stuck it should loosen up, usually start wire from switch it's a Yellow or Yellow/Red on switch, it depends on year.
Auto parts switch might not work if you have to push key in to choke motor.
If you let me know year of your motor I can look at manual to find out which color is wire to solenoid from switch.

Val

[chucker]

Thanks for the advice.

I took the cover off last night and disconnected the starter lead from the solenoid, tapped the solenoid and hooked it back together and the motor is turning over normally!

I think this is probably a short-term fix, but it gets me on the water this weekend.

Next week when I have some time I think I’m going to try a few of muskier hunters suggestions. What would be the best method of troubleshooting if the systems are working? Is it most likely the solenoid based on the fact that it worked after tapping it?

Thanks

Chucker

[musky hunter]

I think you've got it narrowed down to the solenoid. The best and surest fix is to get the solenoid replaced, and that is normally a simple task. The replacement is probably a socket and screwdriver type of proposition.