15 replies to this topic

[Chappy]

I just read Dans post before starting this thread, about his ign switch, and Heres is my sad story.
My MF10 was running fine. I put the snow blower on and was getting ready to fire it up to test it all out.
I turned the ignition switch and something in the switch went poof, and it wouldn't return from strt to run, I also heard a sizzle or zzzzzzzzzz down the line before I turned the key back manually. I grabbed another 5 pin switch from a snapper that fit right in and had the same works, ( acces, on , start) replaced the old switch with it. The return spring working etc. Turned the key, got nothing. Checked the fuse, it was not burned.
Did a quick cross at the solenoid, and the engine turned over.
I have a new amp meter I am getting ready to install , just in case.This GT has no lights or lighter socket etc, just the ampmeter.
Also wondered about the rectifier box.
There is a safety switch down by the drive pulley with an arm on it. Not sure if that has anything to do with the starting portion of the electrics or not.
Anyhow I'm kinda out of ideas and wondered if any of you fellas might have any ideas or thoughts to share with me about my issue. No snow yet, but I'd like to be ready for when it comes.

Bob

[ducky]

Check that you installed the proper switch. It HAS TO HAVE an "M" terminal on it. Not an "I". This can take out the ignition module. Also check that the terminal configuration is the same as the OEM switch.

[DanP]

If he took it off a Snapper it is probably for an electronic ignition and would not have a M. Mine off a Electronic ignition has a B S D C. That has been very hard to find in after market. I think but I am not sure the M is for the ones with a starter generator.

[bhts]

Check that you installed the proper switch. It HAS TO HAVE an "M" terminal on it. Not an "I". This can take out the ignition module. Also check that the terminal configuration is the same as the OEM switch.

Another thing is make sure all terminals do the same thing as the oem.I have 3 different switches here that look the same and have a m on it but all three do something different and this could cause a more cosly problem then just a key switch.

[MH81]

Yes, I will third the opinion that you have to have the right switch on these. If you are at all unsure, disconnect the battery until you can do some testing. Say a little prayer all is OK.

With the battery disconnected and the wire that goes to the ign system disconnected at the engine, run a continuity check from the + battery cable to the end of the wire that goes to the ign. You should have no continuity. turn the key to off and move from the + to the - battery terminal and check that same ign wire again, you should have continuity. If you have any questions - ask. These guys are great & we all want that Techumseh running soon for you... just want to make sure everything is safe first.

[DH1]

Wiring diagram.

[mikebramel]

This is why they put diodes in the newer harness so you dont get any feedback and destroy the module

[Chappy]

Thanks Guys , I know the original was to have a BSDC switch, If that means just 4 posts, then I am really confused since the one on it that was running had 5 posts , like the one from the snapper I used as a replacement. But I will check the switch to be sure.

Is it possible that if the ampmeter was damaged , it would interupt the ignition side?????. I have to admit that I love working on these machines, but when it comes to electronics I am at a loss unless its a slotcar.

Ducky Dan and Bob, I will check the switch to be sure, but as I said the one that went poof (it had been working for months prior)
had 5 posts , same as the replacement one from the snapper, but now I am wondering if even it was an original or a jimmy rigged replacement. I'll do some more tests and rechecking to be sure. I think it might be an idea to replace the fuse just incase its burnt in an end. This is soldered in, but I am wondering if I can cut it out and replace with a current style 20 amp auto blade type fuse and holder rather that the original glass cartridge style,.
Any thoughts?????
Bob
Doug, Thanks for the electrical diagram, I dowloaded it this afternoon and it is the same one that is in my manual. It is all correct except the accessories side which I dont have any of.

[ducky]

Chappy
Just be sure you do not apply any voltage to the wire that goes to the motor. Leave it unhooked and you should have spark. If no spark the ignition module is the problem.
Let me know.

[Chappy]

Ducky are you talking about the wire from the ignition switch to the motor direct ,,, or the wire that goes to the module befor splitting into 2 wires to the motor.
Bob

[MH81]

Chappy, he is talking about the single wire. I believe it's on the terminal marked D? On that diagram, it's labeled pink as a color. Most go to the front of the engine under a screw with another wire.

Like said above, disconnect that wire and Ck spark. Make sure the other wire under that screw is not touching ground by accident but don't tape it all up. If the engine starts, you will need to short this to ground to shut it off.

[ducky]

Chappy, he is talking about the single wire. I believe it's on the terminal marked D? On that diagram, it's labeled pink as a color. Most go to the front of the engine under a screw with another wire.

Like said above, disconnect that wire and Ck spark. Make sure the other wire under that screw is not touching ground by accident but don't tape it all up. If the engine starts, you will need to short this to ground to shut it off.

Ditto!

[Chappy]

Thanks guys, I will give that a try tomorrow, the GT Queen had me out Christmas shopping today, so no time to play.
I'll let you know how I make out with it.
Thanks again
Bob

[Chappy]

Eureka
Well never having much luck with things electronic , it was do or die trying.
The ignition switch as it turns out was not the original 4 spade switch , but it had been working.
Bottom line I figured that I should start where things went wrong,,,, THE SWITCH.
I took it apart and replaced a broken bakelite keyway and turn mechanism with a spare I had salvaged.
I wasnt sure if the contact blade should be wide at the top or at the bottom but it was a 50/50 chance.
So I put it back together, tested it with the continuity tester and it seemed OK. This morning I reinstalled it
in the Massey and cranked it over.....EUREKA,, tha Massey with the Snow Blower is alive and kicking, and ready to go.
Thanks to all those who helped me out with info.
Your a great bunch.
Bob

[MH81]

Glad to hear it's working. Great when a resolution happens!
Thanks for the followup.