Mag 20 starter spins but doesn't engage ring gear

gdheck · #1 11-16-2014, 08:09 PM

Just like the title says, I have a mag 20 that the starter spins, but does not kick the gear out to engage the ring gear. The starter was supposed to be serviced by the dealer where I bought the 2072. He is in the electrical repair business as well as being a mower dealer, but I personally wouldn't take anything to him. It has done this before, but I could always just quit cranking and try again and it would crank just fine. It also acts like it doesn't have the power to crank the engine very fast. It has good cables, I have used a known good battery out of my 1450 and even jumped it off of my 1782 (with a car size battery and 40A alternator conversion) without any better results. Am I in for replacing the starter or is there something else I need to be checking.
Thanks,
Geoffrey

J-Mech · #2 11-16-2014, 08:19 PM

The bendix on that starter is just a screw. In other words, when the starter kicks in it literally "screws" the gear up to the flywheel. Most of the time some lube on it helps. WD-40 to free it up, oil or light grease to make it stay that way. It's better to do this to a removes starter. Bad news is, they're a PITA to remove. If it's not cranking very good, it may be on the way out, which would also make it not jump out well. If you've hooked it to a car battery without better results, you either have a bad connection or a worn starter. FWIW, I've heard about a million people say they have good connections. Then they buy a starter and it doesn't fix it...... and find out they had a bad connection. I'd be 100% sure it's not a bad connection before purchasing a starter.

FrankF3 · #3 11-16-2014, 09:24 PM

My father's 1862 had a similar problem. He said the battery and connections were good as well. When I looked at it, I found the battery was 9 sheets to the wind, and the negative terminal was all corroded with just a few strands left to make the connection. The starter was not getting enough power really spin up with a snap to push the bendix out there to engage the ring gear. A new battery and cable ends, had it starting with no problem.

J-Mech · #4 11-17-2014, 01:33 AM

Quote:

Originally Posted by FrankF3

My father's 1862 had a similar problem. He said the battery and connections were good as well. When I looked at it, I found the battery was 9 sheets to the wind, and the negative terminal was all corroded with just a few strands left to make the connection. The starter was not getting enough power really spin up with a snap to push the bendix out there to engage the ring gear. A new battery and cable ends, had it starting with no problem.

See...... perfect example! Thanks Frank!

gdheck · #5 11-17-2014, 02:14 AM

Ok, I'll double check the cables tomorrow and check the voltage getting to the starter.

I did see on another site that the poster had to extend the bendix all the way and spray cleaner on the drive to degrease it. I hadn't thought of it, but the dealer said he lubed the starter. It may just be that it needs cleaned. I really doubt it, but it's worth a try.

mickb72 · #6 11-17-2014, 08:08 AM

Quote:

Originally Posted by gdheck

Ok, I'll double check the cables tomorrow and check the voltage getting to the starter.

I did see on another site that the poster had to extend the bendix all the way and spray cleaner on the drive to degrease it. I hadn't thought of it, but the dealer said he lubed the starter. It may just be that it needs cleaned. I really doubt it, but it's worth a try.

You should also take the starter apart and clean it. Check arm,brushs,comm, there's a writeup from Matt G on this somewhere. Mike