20C Starter Issues

[Mike 20C]

I have a 1979 Massey Ferguson 20C tractor with loader and a gasoline engine. It had a rebuilt starter when I bought it. At that time, the starter didn't want to engage... very infrequently, but eventually did engage. Recently, this issue has become daily. Here's what I know:

The starter is the correct one for my tractor.
The starter is in good working order.
Voltage, cables, ground are all good.
Ignition switch is good... and new.
Ring gear and starter gear teeth are good.

The sides of the ring teeth appear to be have markings where the Bendix has spun into them, and not fully engaging. See attached photos.

I have tried 1/16", 1/8", and 1/4" worth of shims between the starter and the block. This does not fix the issue. I have found out that there are no factory shims for this tractor. It is a 2 bolt mounting setup so there are no adjustment to be made.

Has anyone else run into this problem, and what fix is out there?

Thank you for any information and advice.

- Mike

 

[stourpaine]

could it be it has the wrong pinion gear on the starter? SOME starters you can adjust how far the pinion gear travels by a eccentric you turn you can check this by removing the starter then place it in a vice add a ground from a test battery touch positive to the connector where the wire attaches from the key switch. you don't want the gear smashing into the end case should be a small clearance when activated you can hold it there with the + for a few seconds while you look. also check you have a full 12v on the wire from the key to the starter when the key is in the start position

 

[joe--h]

Here's an off the wall guess for you. The picture's not great, but those teeth look square to me.

Is it possible someone put a new ring gear on backward, that there's a bevel on the teeth facing the transmission?

Joe H

 

[Tinkerer]

Just because the stater was newly (?) rebuilt does not mean that cannot be defective.
You are describing a classic example of a defective solenoid and /or Bendix drive.
Get a new starter and be sure it has the correct number of teeth on the pinion gear for your particular tractor.
There is a possibility that your rebuilt starter is for a diesel engine. If it is the pinon gear on it is the wrong one for your gas motor.

 

[Vetech63]

How much of the ring gear teeth are left? Shimming the starter will make it worse.

 

[Delmer]

Those teeth look good, the little contact wear I see is normal, I only see two teeth that have any more than a trivial amount of rounding on the square edge. I think I can see the bevel on the back side of the teeth as it should be.

How about a more detailed description of what "not engaging" means? We can assume the starter spins and makes some noise like grinding, is that what it's doing? Does it always do this or are there other noises or ways it acts up, and what does it do when it starts normally?

Obviously not all of your statements are likely true, the starter bendix is either broken, dirty, worn. Or the voltage at the starter is not adequate to spin the starter forcefully. That's the most likely causes I can guess.

 

[stourpaine]

a full 12v on the starter solenoid from key wire as I mentioned in my earlier post is very important its what's drives the Bendix into the ring gear so check for a voltage drop there. if you don't have it you can use a old trick often used on skidders hook uo a relay near the starter with a good 12v supply and use the starter wire that hooks onto the solenoid to trigger it for a full 12v supply. one tooth wrong on the starter drive will really cause engagement problems believe me ive been there! you will barely notice the difference when side by side, as was mentioned before by Joe-h possibility ring gear install problem but check out the easier things first before splitting the tractor in half

 

[Tinkerer]

Not all ring-gears are beveled on one side.
I have purchased and installed ring-gears that were not beveled on either side and the starter had no problem with them.

 

[joe--h]

Easy enough to check, stick your finger in & you'll know.

But it's just a guess.

So what kind of noise do you get when you try to start? Clank or grinding?

Is the starter spinning and grinding the teeth or just clank when bendix hits the teeth?

And a rebuilt starter would be my first guess before the ring gear as most of them are crap. That sticker tells me a big rebuilder, not a local electrical shop = crap.

Joe H

 

[Mike 20C]

Here's an off the wall guess for you. The picture's not great, but those teeth look square to me.

Is it possible someone put a new ring gear on backward, that there's a bevel on the teeth facing the transmission?

Joe H

Joe,

Good thought for sure and it is difficult to tell from the picture, but there is indeed a beveled edge on the ring gear teeth. The ring gear is installed properly.

Thanks.

 

[Mike 20C]

Easy enough to check, stick your finger in & you'll know.

But it's just a guess.

So what kind of noise do you get when you try to start? Clank or grinding?

Is the starter spinning and grinding the teeth or just clank when bendix hits the teeth?

And a rebuilt starter would be my first guess before the ring gear as most of them are crap. That sticker tells me a big rebuilder, not a local electrical shop = crap.

Joe H

Joe H,

This was an infrequent issue the previous owner told me about when I bought the tractor with this very starter on it. He indicated the problem began shortly after he installed this particular starter. I have had the starter tested by a reputable company and it was serviced and tests-out with no issues. The question of proper voltage was brought up by another viewer which got me to thinking. I replaced the original ignition switch about a year ago as it was worn and a possible solution. The replacement switch then burned up about a two months ago. I've replaced it with one from the same vendor but I now question if these switches are internally weak. I've replaced the original key switch/ignition/start/circuit wires with new of the same gauge but I wonder about them at this point as well... being of the same gauge. I say this because of the other viewers question about voltage... it got me thinking about amperage. I realized that the starter spins faster and tries to engage the ring more aggressively when I "jump" the solenoid with a screwdriver or pliers handle. Doing this doesn't make great contact points but it did provide a possible solution. I'm going to install a relay to provide a more increased, and positive, current flow to the solenoid. We'll see if that makes a difference.

Thank you for the thoughts.

- Mike

 

[Mike 20C]

a full 12v on the starter solenoid from key wire as I mentioned in my earlier post is very important its what's drives the Bendix into the ring gear so check for a voltage drop there. if you don't have it you can use a old trick often used on skidders hook uo a relay near the starter with a good 12v supply and use the starter wire that hooks onto the solenoid to trigger it for a full 12v supply. one tooth wrong on the starter drive will really cause engagement problems believe me ive been there! you will barely notice the difference when side by side, as was mentioned before by Joe-h possibility ring gear install problem but check out the easier things first before splitting the tractor in half

Stourpaine,

Your thoughts about voltage got me thinking about amperage.

I replaced the original ignition switch about a year ago as it was worn and a possible solution. The replacement switch then burned up about a two months ago. I've replaced it with one from the same vendor but I now question if these switches are internally weak. Additionally, I've replaced the original key switch ignition/start/circuit wires with new of the same gauge but I wonder about them at this point as well... being of the same gauge. After all of this and the issue still existing, I thought about amperage. I realized that the starter spins a bit faster and tries to engage the ring more aggressively when I "jump" the solenoid with a screwdriver or pliers handle. Doing this doesn't make great contact points but it did provide a possible solution. I'm going to install a relay to provide a more increased, and positive, current flow to the solenoid. We'll see if that makes a difference.

Thank you for your thoughts.

- Mike


Thank you for the thoughts.




- Mike

 

[stourpaine]

my guess is you will see a improvement as you are saying that while jumping at the solenoid it tried to engage more aggressively however will be no different than you shorting from the starter + cable to the solenoid 12v key supply wire.so if it didn't engage with the shorting Assuming you have a full 12v supply to the starter motor it wont either with the addition of the relay.my money is on the pinion and ring gear dont match

 

[Mike 20C]

Stourpaine,

I confirmed a while back that I have the correct starter, and it did work fine for a time.
One of my initial thoughts is that this remanufactured starter has become weak, however, a very reputable electrical shop gentleman has confirmed that it is in good working order. Be it wiring or voltage/amperage, the starter is not engaging.

I'm not able to work on it for a few days but I'll review all my efforts and see what I come up with.

Again, thank you for your thoughts.

- Mike

 

[edgephoto]

Do you have a volt meter?

Do you have a wiring diagram?

With those two tools I can give you some tests to make that will diagnose your problem instead of guessing.