Starter motor not engaging with flywheel

[marty53]

Hi there everyone,

I have a '91 75hp mariner 3 banger. I've had intermittent issues with my starter just spinning and not engaging the flywheel over the last year, but now it doesn't work at all. I've read several threads on here about this, and I think I've tried everything.

heres what I've done:
-fully charged battery (recently passed load test)
-removed all cables from solenoid, starter, and battery and polished them to a shine, also battery posts
-put a couple drops of oil on the starter above the bendix

turn the key, starter still just spins fast but does not shoot up and engage with flywheel.

-next I jumped the starter with booster cables from ground on battery to ground on block, positive to post on starter, and the starter still just spins and doesn't shoot up.


Am I right on diagnosing a failing starter here?

THANKS

 

[oldman570]

Re: Starter motor not engaging with flywheel

The bendix gear is gumed up on the starter shaft and needs to be cleaned and relubed as it will not spin up the shaft. Easy fix. Remove the starter from the motor and put in a vise. hold the nut on the sterter shaft with a wrench and turn the gear up the shaft and clean the shaft and gear while doing so. Then use light oil like 3 in 1 oil to lube the shaft and gear when clean. Test buy using jumper cables while clamped good in vice, for working order. Replace on motor and try to start while on muffs.
Oldman570

 

[marty53]

Re: Starter motor not engaging with flywheel

Thanks oldman, I will pull it off and try cleaning it up this evening. I will report back

 

[marty53]

Re: Starter motor not engaging with flywheel

OK.. so I pulled the starter off, and cleaned and lightly lubed the shaft above the bendix with 3 in 1 oil. I just tested the starter on and off the engine and recorded some videos to show what its doing.

First, here it is on the motor, this is the same thing it does right now when I turn the key on the ignition:

http://youtu.be/7jzVTKXlxkM

Second, here it is in a vise, with a voltmeter attached to the battery.

http://youtu.be/fFZXBaHDgos


It seems to just rise a little bit for a second in both situations, but obviously not enough to engage the flywheel. Is this thing toast at this point?

THANKS

 

[oldman570]

Re: Starter motor not engaging with flywheel

The starter should work when on the motor as the second vidio shows it spining up the shaft now and it is being pushed back down as it should by the return spring. It will stay in the up position when on the motor as it engages the flywheel and has pressure on it till the engine starts and throws it back down. If it just sticks in the flywheel and not spin the motor now the brushes need replaced and the armiture cleaned up. Best to take it to a rebuild shop for getting this done and not as expensive as a new starter.

 

[Texasmark]

Re: Starter motor not engaging with flywheel

The starter should work when on the motor as the second vidio shows it spining up the shaft now and it is being pushed back down as it should by the return spring. It will stay in the up position when on the motor as it engages the flywheel and has pressure on it till the engine starts and throws it back down. If it just sticks in the flywheel and not spin the motor now the brushes need replaced and the armiture cleaned up. Best to take it to a rebuild shop for getting this done and not as expensive as a new starter.

Ditto

 

[SuperYooper]

Re: Starter motor not engaging with flywheel

I agree with oldman570. I had the same issue with an older Mercury starter. Upon tearing it apart, two of the brushes were so worn they became detached form the wires. The brush kit should only run about $24.

 

[marty53]

Re: Starter motor not engaging with flywheel

I agree with oldman570. I had the same issue with an older Mercury starter. Upon tearing it apart, two of the brushes were so worn they became detached form the wires. The brush kit should only run about $24.

OK guys, so I ordered one of the made in china starters on the internet for <$100 and it arrived today. Installed it and works fine--suprisingly. It sounds a lot more clunky than the last one, but it fires her up, and hopefully it will last me a couple seasons. In the meantime I will hold on to the old starter (ARCO brand) and rebuild it as a backup. Needed to get on the water for a island camping trip next weekend.

I figured it was the starter from the beginning but the reason I posted here was because of all the threads I read saying its usually NOT THE STARTER with my symptoms. Thanks for all your help!