68 Electro no spark

[Slightly Discombobulated 6]

I need some help. I picked up a 1968 electro 12 (1-7235) that I'm assuming is an early model built with a leftover 67 engine because the engine patina matches the tractor and it has an external generator/starter instead of the magneto. It's a k301S-4712B. I bought it knowing that the engine turns freely and that it had no spark. Being 52 years old I figured it deserved some fresh ignition parts so I replaced the coil, condenser, points (cleaned and set to .020), spark plug (.035), and plug wire, and I still cannot get a spark at the plug or through my spark plug tester. It turns over okay and I've got 12 volts to the positive terminal on the coil. It's been many years since last worked on this type of ignition system and I'm stumped.  I would appreciate any input/suggestions you might have.  If it were something newer I'd suspect a safety switch but I can't see that this has any.

[Pullstart 62,888]

 

To be sure, that machine should have an internally resisted coil.  The points gap might be happier around .018”, but that shouldn’t prevent spark all together.  Did you confirm there is power at the coil during cranking, or just with the key on?  An incorrect ignition switch could be the culprit.

[953 nut 55,241]

Take another look at the ignition points, with the ignition key "on" you should be able to see a spark there when you open the points with a non-conductive item like a pencil. Is the wire from the points to the coil "-"/condenser in good condition?

[Achto 27,577]

 

If all of the above suggestions check out. Turn the engine over until the points are closed. Then pry them open & put a dollar bill between the contacts. Let the contacts close & pull the dollar bill through them. Do this several times, it will clean any residue off from the points. New points some times have residue on them for shipping purposes.

[ohiofarmer 3,276]

 Ok, since you are a newbie, make sure that you depress that brake pedal fully when you crank it. There is a very hard to see safety switch underneath the "clutch/brake ' pedal.

 On another note, it is no big deal if the electronic coil is knackered on your tractor. Easy and cheap to convert to a coil/condenser if need be.  Here is the internal coil replacement if you need one.

https://isavetractors.com/ignition-coil-for-magneto-ignition-system-for-kohler-k141-k161-k181-k241-k301-engine/

[953 nut 55,241]

7 hours ago, ohiofarmer said:

There is a very hard to see safety switch underneath the "clutch/brake ' pedal.

There are no safety switches on 1968 model , that didn't come along until 1972.

Edited November 26, 2020 by 953 nut

[Slightly Discombobulated 6]

9 hours ago, ohiofarmer said:

 Ok, since you are a newbie, make sure that you depress that brake pedal fully when you crank it. There is a very hard to see safety switch underneath the "clutch/brake ' pedal.

 On another note, it is no big deal if the electronic coil is knackered on your tractor. Easy and cheap to convert to a coil/condenser if need be.  Here is the internal coil replacement if you need one.

https://isavetractors.com/ignition-coil-for-magneto-ignition-system-for-kohler-k141-k161-k181-k241-k301-engine/

Thanks for the input. It already has the coil and condensor from the factory and these parts have been replaced although I suppose one could be defective. 

[Slightly Discombobulated 6]

1 hour ago, 953 nut said:

There are no safety switches on 1968 model , that didn't come along until 1972.

 

Edited November 26, 2020 by tlshirley1s@gmail.com

[Slightly Discombobulated 6]

Could a faulty ignition switch be the culprit even though I'm getting 12 volts at the positive coil terminal with the switch on?

[gwest_ca-(File Mod) 11,045]

See if you have power at the coil (+) while cranking the starter. If you do

 

move the tester to the coil (-) while cranking the starter.

As you continually crank the starter the coil (-) should have a power and no power repeating cycle as the points open and close. One cycle for every two rotations of the crankshaft because the camshaft that opens the points rotates at 1/2 the speed of the crankshaft.

 

When the points are open you should have power at the coil (-).

If you do not the wire from the coil to the points is shorted to ground or the points are shorted to ground. Try with points cover off in case it is contacting the points and/or wire. A shorted condenser is a possibility. Remove it from the coil (-) terminal and try again.

 

When the points are closed you should not have power at the coil (-).

If you do the wire from the coil to the points is broken or the points are not making electrical contact when closed. (Misadjusted or dirty)

 

The first 1968 Chargers used the engine you have. Mid-model year they switched to the Bendix starter and charging stator but continued to use the same tractor model number. Bet they regretted that.

An Electro is a Charger plus options.

 

Garry

[squonk 41,118]

What Gary said. With a test light, The coil negative terminal should blink (flash) whilst cranking. This primary circuit needs to "drop out" to induce the high voltage magnetic field through the coil secondary winding, through the coil high tension wire ,through the spark plug to ground.

[ohiofarmer 3,276]

1 hour ago, tlshirley1s@gmail.com said:

Could a faulty ignition switch be the culprit even though I'm getting 12 volts at the positive coil terminal with the switch on?

 They do wear out. They can light a voltage meter, but really are not feeding through enough amps to do the job. A test light can reveal weak connections  and saved my bacon just the other day. Also a previous owner may have the incorrect switch installed. I just found that very issue. The PO had a 4 position switch installed that had the correct 5 pins to hook to the harness. That extra switch position killed the deal and it did not work. The same tractor had a loose wire termination to the regulator that feeds the power to the ignition switch [I think} Two electrical problems at once makes for a fun day.

  Isavetractors will give you the correct switch for your tractor even though they may cost $5 more. Sometimes it's worth it. Or use the vendors that sell here to remain focused on quality.

Edited November 26, 2020 by ohiofarmer

[Slightly Discombobulated 6]

2 hours ago, ohiofarmer said:

 They do wear out. They can light a voltage meter, but really are not feeding through enough amps to do the job. A test light can reveal weak connections  and saved my bacon just the other day. Also a previous owner may have the incorrect switch installed. I just found that very issue. The PO had a 4 position switch installed that had the correct 5 pins to hook to the harness. That extra switch position killed the deal and it did not work. The same tractor had a loose wire termination to the regulator that feeds the power to the ignition switch [I think} Two electrical problems at once makes for a fun day.

  Isavetractors will give you the correct switch for your tractor even though they may cost $5 more. Sometimes it's worth it. Or use the vendors that sell here to remain focused on quality.

There a way to test the switch? 

 

[gwest_ca-(File Mod) 11,045]

Is this what the back of the switch looks like and terminals identified the same?

Click on the picture

Off key position - none connected

Run key position - BATTERY and IGNITION connected

Start key position - BATTERY IGNITION START connected

 

Garry

[pfrederi 17,739]

If you switch looks like the picture Gary provided do this test.  using a heavy jumper cable connect to the B terminal and then touch the other end to the A terminal on the generator ...she should spin.  If she does and it doesn't when you turn the ignition to start either the switch is bad or eh wire from it to the Generator is bad.

[Slightly Discombobulated 6]

2 hours ago, gwest_ca said:

Is this what the back of the switch looks like and terminals identified the same?

Click on the picture

Off key position - none connected

Run key position - BATTERY and IGNITION connected

Start key position - BATTERY IGNITION START connected

 

Garry

I was able to snap a picture without removing the fuel tank. It looks like the wrong switch  to me. I see the letters S, B, L, M and R with a tab between the M and R. This pretty much matches a diagram I found for a later model ignition system with the exception of M and R being connected together, and there are only 4 screw terminals.   The wiring definitely needs some work also. 

Edited November 26, 2020 by tlshirley1s@gmail.com

[Slightly Discombobulated 6]

1 hour ago, pfrederi said:

If you switch looks like the picture Gary provided do this test.  using a heavy jumper cable connect to the B terminal and then touch the other end to the A terminal on the generator ...she should spin.  If she does and it doesn't when you turn the ignition to start either the switch is bad or eh wire from it to the Generator is bad.

The generator and engine spin fine when the switch is turned. I'm just not getting spark. I'm thinking the switch is at fault or there is a short to ground somewhere. I can't imagine what else it could be. 

[pfrederi 17,739]

A switch marked with an M will not work for you.

[gwest_ca-(File Mod) 11,045]

This looks like the switch you have and would be correct for late 1968 models with magneto ignition.

Look up under the dash panel for the ID plate and post the serial number of the tractor. It may not be the original engine to the tractor.

 

Garry

[squonk 41,118]

3 hours ago, tlshirley1s@gmail.com said:

I was able to snap a picture without removing the fuel tank. It looks like the wrong switch  to me. I see the letters S, B, L, M and R with a tab between the M and R. This pretty much matches a diagram I found for a later model ignition system with the exception of M and R being connected together, and there are only 4 screw terminals.   The wiring definitely needs some work also. 

I see some BAD WIRES!

[953 nut 55,241]

3 hours ago, pfrederi said:

A switch marked with an M will not work for you.

Looks like the "M" terminal isn't being used in the photo. Take a small jumper wire from the battery "+" to the coil "+" and crank it over. If it is the ignition switch that is your problem it will have spark with the jumper in place.

[ohiofarmer 3,276]

3 hours ago, 953 nut said:

Looks like the "M" terminal isn't being used in the photo. Take a small jumper wire from the battery "+" to the coil "+" and crank it over. If it is the ignition switch that is your problem it will have spark with the jumper in place.

 

           yeppir. I use jumper wires with alligator clips a lot. sort of like having a third hand. Not nearly as smart as a lot of the guys here, but I stumble through. Just never assume anything left there by a previous owner is correct.

Edited November 27, 2020 by ohiofarmer

[953 nut 55,241]

If your ignition switch is the problem you may want to consider adding a solenoid and replacing the ignition switch with a 103-990. That will cost a lot less than buying an OEM replacement switch (if you could even find one) and it gets the high amperage battery cables away from the plastic gas tank.

[Slightly Discombobulated 6]

12 hours ago, ohiofarmer said:

 

           yeppir. I use jumper wires with alligator clips a lot. sort of like having a third hand. Not nearly as smart as a lot of the guys here, but I stumble through. Just never assume anything left there by a previous owner is correct.

 

16 hours ago, 953 nut said:

Looks like the "M" terminal isn't being used in the photo. Take a small jumper wire from the battery "+" to the coil "+" and crank it over. If it is the ignition switch that is your problem it will have spark with the jumper in place.

Problem solved. Thanks to all of you for your suggestions and a special shout out to Ohio Farmer for the suggestion to use a jumper from the battery to the coil.  It started so fast it surprised me. Last ran a couple of years ago and started without even a puff of smoke.

[ohiofarmer 3,276]

The special shout out should belong to 953 nut. All i did was agree with him...I am very happy that your tractor is running