John Deere MT no spark

I have a 1949 MT. It has no spark. Here?s the back ground...it has not been run in 4 years. It rolls over fine. I put new, points, condenser, cap, coil on.
I am not getting any spark coming out of coil using in line spark tester. Shouldn?t I be? With the cap off I am not seeing any spark at points either. Any
help on what to do next would be great I would like it running! Thank you in advance.

Hey mt,
Check the fuse behind the battery. Probably blown or not making a good connection. Sometimes they get blown if your jumping it to get it to turn over. To test, run a jumper off the battery to the coil and see if it has spark. Good Luck!
John

"I am not getting any spark coming out of coil using in line spark tester. Shouldn?t I be?" YES

"With the cap off I am not seeing any spark at points either." Typically you see a small spark there as they open and close


NEW POINTS may have a thin film of protectant that needs cleaned off and dried for them to work properly, check that out

Are they gapped correct and open n close fully???

A common cause of no fire IS DIRTY OR CORRODED OR OXIDIZED POINTS Try to clean and check gap and insure they are fully opening and closing as the distributor rotates. If not bad looking try dragging a dollar bill through them which may clean off light oxide.

Is there voltage on the coils input with Ignition ON ??? THERE MUST BE or else the Ignition switch may be bad, try jumping a temporary hot wire direct to the coils input n see what happens ???

A test lamp over on the coils output TO DISTRIBUTOR with ign on and engine cranked over must flash ON when points are open and OFF when closed. Does it??

Sure you have the points and condenser wired correct???

If all fails try my simple troubleshooting which requires mostly just your eyes perhaps a 6/12 test light KEEP IT SIMPLE


http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=5745

John T
John Ts Ignition Troubleshooting

Thanks for all the information. I know I do have power on the input of the coil with switch on. I checked with a test light. How could condenser be wired wrong? There is only one wire and one place to wire it, with the points. Does the bolt going out the side of the distributor act as a ground? Could that need cleaned? That is where points and condenser wire up.
I will check the fuse idea tomorrow too.
Thanks

"[b:654c4848f0][i:654c4848f0]I am not getting any spark coming out of coil using in line spark tester[/i:654c4848f0][/b:654c4848f0]"

Take a look at the photo below.



If the in line spark tester does not flash as the motor turns over, then you might consider checking both terminals on the coil using a test light.

Turn the ignition switch to the LO CHARGING position.



Next check the NEGATIVE terminal for power coming from the ignition switch.



If the test light shines, then there is power to the coil; otherwise check the ignition switch and/or the lead wire from the ignition and accessory terminal.



Next check the POSITIVE terminal for power from the coil.



If the test light shines, then there is power through the coil; otherwise replace the coil.

Next check for power at the distributor terminal stud.



If the test light shines, then there is power from the coil; otherwise repair/replace the lead wire to the distributor.

Next check for power inside the distributor.



Note the stud terminal bushing.

Next check for power at the terminal stud inside the distributor.



If the test light shines, then there is power from the terminal stud to the points; otherwise check the stud terminal bushing.

Next check for power from the points.



If the test light shines, then there is power from the points.

"[b:654c4848f0][i:654c4848f0]With the cap off I am not seeing any spark at points either[/i:654c4848f0][/b:654c4848f0]"

Check the points gap and adjust to .022 if necessary.



[b:654c4848f0][i:654c4848f0]<font color="#ff0000">Please be mindful of common safety steps; expressed or not.[/i:654c4848f0][/b:654c4848f0]</font>

Turn the ignition switch to the LO CHARGING position.

Crank the engine and check for spark at the points.

If there is a spark when the points OPEN, then the primary circuit is working; otherwise you might consider replacing the condenser.

We have one MT that has gone through many condensers; even new ones.

In regards to the coil, you might also consider checking the coil wire to the distributor.

Hope this helps.

"[b:654c4848f0][i:654c4848f0]How could condenser be wired wrong? There is only one wire and one place to wire it, with the points[/i:654c4848f0][/b:654c4848f0]"

Only if it is NOT connected at the stud terminal.

However, it must be secured to the breaker plate by, for lack of a better term, the condenser [i:654c4848f0]saddle[/i:654c4848f0].



"[b:654c4848f0][i:654c4848f0]Does the bolt going out the side of the distributor act as a ground?[/i:654c4848f0][/b:654c4848f0]"

No.

Current passes through the stud terminal which is insulated from [i:654c4848f0]grounding[/i:654c4848f0] by the terminal stud bushing.

Hope this helps.

The distributors side pass through stud is insulated off the case and is where the wire connects from the coils output and inside it wires to the points. It should NOT BE GROUNDED TO THE CASE but I have seen the black plastic insulation fail and short them out.

A test lamp on the coils output (to that pass thru stud) with ignition on and engine rotated MUST flash ON when points open and OFF when they are closed. See my procedure for more detail

If you need more just work through my Troubleshooting Procedure and post back findings and any questions

John T
Ignition Troubleshooting

first thing i sways did was a check as resting relics posted. I assume the starter is like on a 420. i always grabbed the end of the cable coming off the batt at the starter, Handier I thought.

Thank you everyone for your help and pictures. I replaced the wire from the coil and cleaned the connection. Cleaned the points again and it started right up!

I spent a lot of time cleaning the connections on the switch didn?t help so I cleaned the connections on the starter and had spark so keep checking connections