Mercury 40hp starter just spins- won't engage

[Bill Collector]

I have a 1982 mint merc 40 that runs great but is extremely tempermental. Yesterday the starter gear would not engage the flywheel. I would then manually turn the starter gear and get it to climb up the shaft to touch the fly wheel and then release it. I would try the key and it would work no problem for one or two times and then just the gear would spin again. I got home and lifted the gear and sprayed a little silicone in there figuring it was just sticking. The engine then started consistently about 10 times. What could cause this and should I just buy a new starter now? What's the symptom of the starter just spinning like that and not engaging? Big weekend ahead and I want this thing running perfect.

 

[1960 Starflite]

Re: Mercury 40hp starter just spins- won't engage

Sounds like the Bendix is hanging up. You don't need a new starter, it's just a motor. The bendix is held together by a circle clip or snap ring on the end of the motor shaft. Pull the starter off, so you don't drop parts in the water. Remove the circle clip and pull the complete Bendix off. It sorta unscrews apart. Clean the parts and put a little grease on the sprial thread leads.

Sometimes, if the battery is low, the starter motor wont spin fast enough to engage the Bendix.

 

[windy5849]

Re: Mercury 40hp starter just spins- won't engage

+1 ^^^^ But I would use a light weight oil on the bendix shaft.Grease becomes sticky when it gets colder.

 

[bktheking]

Re: Mercury 40hp starter just spins- won't engage

3in1 works well for this type of application, may also be bad contact at the battery or corroded cables.

 

[CharlieB]

Re: Mercury 40hp starter just spins- won't engage

If the drive gear moves freely on the starter shaft then the problem is the starter motor is not spinning up to speed quick enough to screw the drive up the shaft.

Usually this is caused by a poor connection, both ends of all cables must be clean, bright, and tight.

An intermittant occurance is often a sign the contact plate inside the starter relay is loosing contact in some places, as the plate rotates it works fine, then other times fails.

If all else checks out fine replace the relay/solenoid.

 

[Rocky L]

Re: Mercury 40hp starter just spins- won't engage

I have a 1982 mint merc 40 that runs great but is extremely tempermental. Yesterday the starter gear would not engage the flywheel. I would then manually turn the starter gear and get it to climb up the shaft to touch the fly wheel and then release it. I would try the key and it would work no problem for one or two times and then just the gear would spin again. I got home and lifted the gear and sprayed a little silicone in there figuring it was just sticking. The engine then started consistently about 10 times. What could cause this and should I just buy a new starter now? What's the symptom of the starter just spinning like that and not engaging? Big weekend ahead and I want this thing running perfect.

I had the same problem. Removed the starter and then manually lifted the Pinion Gear to expose the threds on the shaft. Thoughly cleaned the threads, applied lube grease and reinstalled. That did the trick. Some times grome and metal filings clog up the threads and prohibit the starter gear from traveling up the threads to engage the fly wheel.

 

[bruce richardson]

i have the same issue after replacing the solenoid and starter ; because of starting issues; put the old starter back in and it did the same ; positive battery terminal very hot. 1996 mercury 40 hp force

 

[Fun Times]

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