No Spark - What Ign Key Sw should I use

[george.stringer@frontier.c 0]

I have a late 1968 Wheel Horse Model No. 7231 Charger 12 with a Kohler 12K302-S Spec. No 47147 8.  The coil is in the stator under the flywheel and the points are under a tin cover on the front of the engine.  There is no solenoid and the 4 position ignition switch has the S and B terminals with screws in them to hold the big wires that go direct the Battery and Starter.  There is no spark when I crank.  The "M" terminal on the key switch shows continuity to ground in the off position as it should.  In the run position there is no continuity to L or R, but there is continuity to M and S.  In the start position there is continuity to S and M, but not to L while cranking.   A diagram on the internet says that there should be a circuit to B+L+R in run and in start a circuit only to B+S.  M should not show continuity,  Right?   I am not getting R in either Run or Start and I am getting M in both Run and Start.  Two Question?  What is the part number of my ignition switch and do I need a new one or do I need a new coil? 
 

[gwest_ca-(File Mod) 11,358]

This should be the manual to your tractor
http://www.wheelhorseforum.com/files/file/1761-tractor-1968-charger-12-late-production-da-om-ipl-wiringpdf/

Certainly sounds like your ignition switch has failed. The original part number is 7572 and is replaced by 101482 still available from Toro. When you get one make sure it has an M terminal and no I (eye) terminal.

Can't answer you on the ignition coil. Remove the ignition wire from the M terminal on the switch and isolate it so it touches nothing. Try it. If it starts the ignition is OK and to shut it OFF simply ground the ignition wire to the chassis metal or ground. If it does not run try cleaning the point contacts with a points file or a nail file. They can get invisible oxidation/corrosion on them that will prevent electrical contact. After disturbing the contact surfaces drag a strip of clean white paper through them until it comes out clean or use an aerosol contact cleaner.

Let us know what you find.

Garry

[george.stringer@frontier.c 0]

I have a late 1968 Wheel Horse Model No. 7231 Charger 12 with a Kohler 12K302-S Spec. No 47147 8.  The coil is in the stator under the flywheel and the points are under a tin cover on the front of the engine.  There is no solenoid and the 4 position ignition switch has the S and B terminals with screws in them to hold the big wires that go direct the Battery and Starter.  There is no spark when I crank.  The "M" terminal on the key switch shows continuity to ground in the off position as it should.  In the run position there is no continuity to L or R, but there is continuity to M and S.  In the start position there is continuity to S and M, but not to L while cranking.   A diagram on the internet says that there should be a circuit to B+L+R in run and in start a circuit only to B+S.  M should not show continuity,  Right?   I am not getting R in either Run or Start and I am getting M in both Run and Start.  Two Question?  What is the part number of my ignition switch and do I need a new one or do I need a new coil? 
 

​

This should be the manual to your tractor

Certainly sounds like your ignition switch has failed. The original part number is 7572 and is replaced by 101482 still available from Toro. When you get one make sure it has an M terminal and no I (eye) terminal.

Can't answer you on the ignition coil. Remove the ignition wire from the M terminal on the switch and isolate it so it touches nothing. Try it. If it starts the ignition is OK and to shut it OFF simply ground the ignition wire to the chassis metal or ground. If it does not run try cleaning the point contacts with a points file or a nail file. They can get invisible oxidation/corrosion on them that will prevent electrical contact. After disturbing the contact surfaces drag a strip of clean white paper through them until it comes out clean or use an aerosol contact cleaner.

Let us know what you find.

Garry

​Removing the wire at the M terminal had no affect.  Still no spark at the plug.  There are three wires that connect at the points.  One from the condenser, one from the M terminal and one from the stator coil assembly.  It is correct for all therr to be there connected to the points?

[gwest_ca-(File Mod) 11,358]

I have a late 1968 Wheel Horse Model No. 7231 Charger 12 with a Kohler 12K302-S Spec. No 47147 8.  The coil is in the stator under the flywheel and the points are under a tin cover on the front of the engine.  There is no solenoid and the 4 position ignition switch has the S and B terminals with screws in them to hold the big wires that go direct the Battery and Starter.  There is no spark when I crank.  The "M" terminal on the key switch shows continuity to ground in the off position as it should.  In the run position there is no continuity to L or R, but there is continuity to M and S.  In the start position there is continuity to S and M, but not to L while cranking.   A diagram on the internet says that there should be a circuit to B+L+R in run and in start a circuit only to B+S.  M should not show continuity,  Right?   I am not getting R in either Run or Start and I am getting M in both Run and Start.  Two Question?  What is the part number of my ignition switch and do I need a new one or do I need a new coil? 
 

​

This should be the manual to your tractor

Certainly sounds like your ignition switch has failed. The original part number is 7572 and is replaced by 101482 still available from Toro. When you get one make sure it has an M terminal and no I (eye) terminal.

Can't answer you on the ignition coil. Remove the ignition wire from the M terminal on the switch and isolate it so it touches nothing. Try it. If it starts the ignition is OK and to shut it OFF simply ground the ignition wire to the chassis metal or ground. If it does not run try cleaning the point contacts with a points file or a nail file. They can get invisible oxidation/corrosion on them that will prevent electrical contact. After disturbing the contact surfaces drag a strip of clean white paper through them until it comes out clean or use an aerosol contact cleaner.

Let us know what you find.

Garry

​Removing the wire at the M terminal had no affect.  Still no spark at the plug.  There are three wires that connect at the points.  One from the condenser, one from the M terminal and one from the stator coil assembly.  It is correct for all therr to be there connected to the points?

​Yes all three wires can connect to the points.
Do you happen to have an ohmmeter to do some further checking?

Garry

[george.stringer@frontier.c 0]

I have a late 1968 Wheel Horse Model No. 7231 Charger 12 with a Kohler 12K302-S Spec. No 47147 8.  The coil is in the stator under the flywheel and the points are under a tin cover on the front of the engine.  There is no solenoid and the 4 position ignition switch has the S and B terminals with screws in them to hold the big wires that go direct the Battery and Starter.  There is no spark when I crank.  The "M" terminal on the key switch shows continuity to ground in the off position as it should.  In the run position there is no continuity to L or R, but there is continuity to M and S.  In the start position there is continuity to S and M, but not to L while cranking.   A diagram on the internet says that there should be a circuit to B+L+R in run and in start a circuit only to B+S.  M should not show continuity,  Right?   I am not getting R in either Run or Start and I am getting M in both Run and Start.  Two Question?  What is the part number of my ignition switch and do I need a new one or do I need a new coil? 
 

​Yes I do have a ohmmeter.  I used it to test the continuity in the wires from the stator and the positions of the ignition switch.  Thanks for all your help.  I am lost as to what to fix.  George

This should be the manual to your tractor

Certainly sounds like your ignition switch has failed. The original part number is 7572 and is replaced by 101482 still available from Toro. When you get one make sure it has an M terminal and no I (eye) terminal.

Can't answer you on the ignition coil. Remove the ignition wire from the M terminal on the switch and isolate it so it touches nothing. Try it. If it starts the ignition is OK and to shut it OFF simply ground the ignition wire to the chassis metal or ground. If it does not run try cleaning the point contacts with a points file or a nail file. They can get invisible oxidation/corrosion on them that will prevent electrical contact. After disturbing the contact surfaces drag a strip of clean white paper through them until it comes out clean or use an aerosol contact cleaner.

Let us know what you find.

Garry

​Removing the wire at the M terminal had no affect.  Still no spark at the plug.  There are three wires that connect at the points.  One from the condenser, one from the M terminal and one from the stator coil assembly.  It is correct for all therr to be there connected to the points?

​Yes all three wires can connect to the points.
Do you happen to have an ohmmeter to do some further checking?

Garry

​

[george.stringer@frontier.c 0]

Yes I do have an ohmmeter.  I used it to check continuity from the coil to the points and plug.  Also the check the circuits in the ignition switch to the terminals.  Thanks for all your help.  I am lost as to know what to do next.  George

[gwest_ca-(File Mod) 11,358]

There is a test you can do to check the coil.
Remove the spark plug so you can easily turn the engine over to get the points OPEN.
Turn the ignition key to ON so the ignition wire is not grounded by it.

Check the resistance between the ignition wire on the points and the engine block. (Primary coil winding) Should be a very low reading like one ohm or parts of an ohm (.8). It may take a few seconds for the ohmmeter to charge the condenser. If you don't get that remove the points/coil wire from the points in case the points are shorted and use just the points/coil wire less the condenser.

Now  check the resistance between the spark plug wire and the engine block. (Secondary coil winding) Should be a figure like 5K to 6K (5830 ohms)

Now check the resistance between the points/coil wire and the spark plug wire. It should be 5830.8 ohms - the two added together. The figures I've used are from a good B&S coil.

The primary winding and the secondary winding share a ground at the coil. That is why we can do this.

Even if this test checks OK the secondary winding insulation can be compromised and the spark can leak/jump to ground before it gets to the plug. The insulation is aged  and weaker than when new plus these coils are going to fire even if a spark gap is too wide. It may just blow through the insulation. That is why there should always be a well grounded spark plug attached to the plug wire or a grounded tester attached or the plug wire grounded so the secondary voltage is not allowed to go too high for the insulation.

Check the point resistance. Test from the points terminal to the engine block. Points closed - zero ohms. Points open - infinity

If you get this far OK try a new condenser.

Let us know what you find.

If the coil has failed you can easily go to battery ignition because you already have the points. Requires an external coil and a new ignition switch for battery ignition.

Garry

[george.stringer@frontier.c 0]

This should be the manual to your tractor

Certainly sounds like your ignition switch has failed. The original part number is 7572 and is replaced by 101482 still available from Toro. When you get one make sure it has an M terminal and no I (eye) terminal.

Can't answer you on the ignition coil. Remove the ignition wire from the M terminal on the switch and isolate it so it touches nothing. Try it. If it starts the ignition is OK and to shut it OFF simply ground the ignition wire to the chassis metal or ground. If it does not run try cleaning the point contacts with a points file or a nail file. They can get invisible oxidation/corrosion on them that will prevent electrical contact. After disturbing the contact surfaces drag a strip of clean white paper through them until it comes out clean or use an aerosol contact cleaner.

Let us know what you find.

Garry

​

I have a late 1968 Wheel Horse Model No. 7231 Charger 12 with a Kohler 12K302-S Spec. No 47147 8.  The coil is in the stator under the flywheel and the points are under a tin cover on the front of the engine.  There is no solenoid and the 4 position ignition switch has the S and B terminals with screws in them to hold the big wires that go direct the Battery and Starter.  There is no spark when I crank.  The "M" terminal on the key switch shows continuity to ground in the off position as it should.  In the run position there is no continuity to L or R, but there is continuity to M and S.  In the start position there is continuity to S and M, but not to L while cranking.   A diagram on the internet says that there should be a circuit to B+L+R in run and in start a circuit only to B+S.  M should not show continuity,  Right?   I am not getting R in either Run or Start and I am getting M in both Run and Start.  Two Question?  What is the part number of my ignition switch and do I need a new one or do I need a new coil? 

​

This should be the manual to your tractor

Certainly sounds like your ignition switch has failed. The original part number is 7572 and is replaced by 101482 still available from Toro. When you get one make sure it has an M terminal and no I (eye) terminal.

Can't answer you on the ignition coil. Remove the ignition wire from the M terminal on the switch and isolate it so it touches nothing. Try it. If it starts the ignition is OK and to shut it OFF simply ground the ignition wire to the chassis metal or ground. If it does not run try cleaning the point contacts with a points file or a nail file. They can get invisible oxidation/corrosion on them that will prevent electrical contact. After disturbing the contact surfaces drag a strip of clean white paper through them until it comes out clean or use an aerosol contact cleaner.

Let us know what you find.

Garry

​Removing the wire at the M terminal had no affect.  Still no spark at the plug.  There are three wires that connect at the points.  One from the condenser, one from the M terminal and one from the stator coil assembly.  It is correct for all therr to be there connected to the points?

​

[george.stringer@frontier.c 0]

I purchased the suggested replacement ignition switch art Number 101482.  It has the "M" terminal but no "R" terminal.  If I can use this switch where do I put the "R" wire.  Thanks George

[gwest_ca-(File Mod) 11,358]

You have stumped me now. I don't see where either one has an R terminal and these secure the wire with a screw.

This file should illustrate the original 7572 switch terminal locations
http://www.wheelhorseforum.com/files/file/1790-wh61-90-103-ignition-switch-1968-12hp-models-origpdf/

This file should illustrate the replacement 101482 switch terminal locations
http://www.wheelhorseforum.com/files/file/1209-wh61-90-134-ignition-switches-1972-modelspdf/
Download the one named WH61-90 #134 Ignition switches 1972b.pdf

Garry

Edited June 6, 2015 by gwest_ca

[george.stringer@frontier.c 0]

I took my old switch apart and found a hole burned in the rotary portion of the copper contactor that rotates to distribute current to the different terminals.  I took a sheet of copper and made a new one and put it back together.  I have not tried it yet, but it should work as it feels and acts correctly.  I have a question about my new 101482 switch.  I checked the old switch and found that I had continuity between the “B” and “R” terminal in the Run position.  No other terminal had continuity with "R" in the run position.  Since it has no “R” terminal, would it be safe to connect the “R” wire on my W H to the “B” terminal on the new switch?  Thanks George

 

[gwest_ca-(File Mod) 11,358]

See your other post about a solenoid. I replied there.

Garry

[george.stringer@frontier.c 0]

I have looked at both posts and can not find your reply.  Sorry I am not very good with this system.  Thanks George

[gwest_ca-(File Mod) 11,358]

I have looked at both posts and can not find your reply.  Sorry I am not very good with this system.  Thanks George

​You are doing fine. This should take you back there in case you lose it again
​
Garry