782 Starting Issue
 

My 782 is running perfect. Shut it off and now starting circuit is not working. Turn the key to start and nothing.

However I can start it by shorting the starter solenoid terminals and it runs fine.

This is what I've done so far.

-by passed the safety switches ( for testing only )

-replaced the solenoid

-checked for loss wires.

Everything is as it should be.

Next thing I'm thinking is the ignition switch. Could the start part of the switch just stop working ??

If it's not the switch then what else is there ?

I'm open to ideas.

Mike :bigthink:

dunno about the 782's, but my 1250 eats switches like popcorn (more so now since MTD now supplies them at my CC dealer...they are junk I think). on the 1250 the contacts are pretty close together and corrode quickly causing what I think is shorting.

internally I think they can get "loose" and prevent the battery from charging (had one a few years ago that I had to "wiggle" while I watched to charging meter).

pull it and clean it up...see if it helps

Fixed all that crap on my 1210 with a toggle switch and a push button for the starter. It wouldn't start one too many times in the winter when I needed it to plow snow. The Cub wiring harness went in the trash can. Never failed to start or run as it should since. Not one safety switch on it. No I will not tell you how to do it and No I will not sell it as it is, I know the drill. :biggrin2:

I'll do some power tracing through the switch and see what I can learn.

I had the switch out recently and it is old and corroded. The previous owner had power washed the entire tractor and let it rust. I've had to free up everything that moves from the rust.

I kind of like that idea of a toggle and starter button. Don't have to worry about lost key either.

Yep let's wash it and rust it, Gotta love the PO keeping it clean.

Key? We don't need no stinkin Key :biggrin2:

If all the new switches are junk why not change to an old style chevrolet or even a John Deere, I have changed several in years past on my big row crop tractors and none have given any trouble since.

Methinks there's something else wrong that he needs to fix...it should not be eating switches like that.

I don't think so. Everything works fine (i.e generator, starter, grounds) but the switches corrode very quickly (the A, S, and B terminals are very close together. It could be that the OEM plug was missing when I bought it, converted to separate spade connectors). I've seen that others have the same thing and I wonder if there was a problem with it.

You're the first person I have ever heard of having trouble with new OEM switches. Since this doesn't seem to be a widespread problem, I stand by what I've said before...something else is wrong.

The connectors that are in the plug for the switch can corrode, then they arc removing the plating on the switch spades.
then they rust and it is a vicious circle.
Many times you will see a melted plug, a sure sign that the arcing is taking place.
Replacing the terminals in the plug will cure the problem.

I can only speak to the 1250 but this is what the failed switches look like (mine have all looked the same).http://onlycubcadets.net/forum/attac...1&d=1349728607

this one could have been cleaned but I had a new one. note how close the terminals are. the next one...I'll consider replacing the spade connectors (the OEM plug was missing when I bought it suggesting somebody had a problem already).

Back to my 782 issue. It will not crank. Can short the terminals on the solenoid and it cranks and starts right up.

I studied the wiring diagram for this model last night. So the power goes from battery to post on solenoid, through wiring harness to Amp meter, Ignition switch, a couple safety switches and back to the solenoid to the small terminal,
that is then supposed energize the solenoid and put power to the other terminal that goes to the starter.

So tonight I started testing different points along the flow and everything is getting power. I turned the key to start and at the same time tested the voltage at the small terminal on solenoid. Getting about 10.7v. Battery and hot side of solenoid show 12.7v so there's good power.

If I'm getting power back to the small terminal on solenoid it should energize and start. But it's not and this is with a new solenoid. I can here it click a little. But that's it.

So does anyone know how to test a solenoid ? What's the minimum voltage required to energize ?

I'm thinking the old and the new solenoids are bad. But what's the chances of that ?

:bash2: :bash2:

Check your Ground
 

Michics: Good work tracing the starting circuit. But if you're getting a click, the solenoid is working, the problem is that not enough juice is flowing to the starter motor.

I would check your grounds. (1) Remove the solenoid and spend some time getting the frame down to shiny metal before re-attaching the solenoid, also, get some star washers (or Kep-Nuts) if you don't have them to make sure you have a ground at the solenoid. (2) Remove the wire that runs from the negative side of the battery to the frame and repeat the same procedure. I think I even ran a length of 12 gauge wire from the battery ground nut across the battery compartment to the solenoid mount tab when I was having the same trouble you seem to be having.

Note 1: I'm assuming your battery is in good shape, since you can jump across the heavy-gauge terminals at the solenoid and the engine will crank.

Note 2: The way I test a solenoid is out of the tractor with an Ohm meter. There should be a very low resistance from the small terminal to the mounting tab --the meter should only be seeing the resistance of the wire in the coil.

You can also test the resistance across the big contacts by wiring up the solenoid coil, but leaving the heavy gauge wires off. Energize the solenoid and measure the resistance, it should be close to zero. Alternatively, if everything is wired up, you can measure the VOLTAGE across the big terminals and it should also be close to zero. If you find a significant voltage or resistance reading across the big terminals when the solenoid is energized, it indicates a buildup of carbon on the contacts and the solenoid should be replaced, since they're difficult to service --most of them are sealed with rivets and spring loaded.

My two cents. :)

Also make sure that you are getting good voltage through the brake switch. I think that might be the only thing in line with the solenoid.

AJ

Start Circuit
 

AJ: I believe that one side of the PTO switch is also in series with the key and the brake switch. The operator is supposed to be in the seat (Seat Switch is in the Ignition circuit), with the foot on the brake (Brake Switch in Start Circuit) and the PTO is supposed to be switched OFF (one pole of the PTO Switch is in the Start circuit)

Jeremiah

Tonight I took the solenoid out and and tested it directly from the battery. It works perfectly. So reinstalled it, charged the battery a little bit, cleaned up the mounting for ground and it worked. Tractor started. Tried it couple more times and once it hesitated to kick in the starter.

So I figured I wasn't getting a good current flow through the wiring. Started checking more this. The PTO switch is rusty so I pulled out. Severe rust on all the terminals. Could hardly get the connectors off. I pulled the individual connectors out of the plug and cleaned them up with a small file. All shiny now. I'm thinking the extra charge in the battery was just enough to push through some of that rust.

As for the switch. Into the trash for it. Ordered a new one. I going to pull the Ignition switch tomorrow night and clean it up as well.

As you all know, these electrical gremlins can drive you nuts chasing down the root cause. So I think I'm good on this problem.

Thanks to all for the ideas. Also good advice on the grounding suggestions. I will work on that some more to avoid future issue.

Appreciate the help.

Mike :beerchug:

So here's what I believe caused the problem. This is the PTO switch and as you can see it is in bad shape. It's hard to get a good current flow through this mess.

I think you are onto something! does look like it could be cleaned up but it is 32 years old now! I have a knee that didn't last that long.

On your way
 

Michics: Glad you got on top of it, sounds like you're on your way!

DOH!

X2:beer2: