Mag has no spark

[mrkwpatton]

Guys I just bought a 1940 John Deere B today and I have no spark. I pulled the cap off of the mag and cleaned all the points and still have no spark. Is there a way I can test the mag without any wires plugged into it because the wires don"t look that great? Any help would be greatly appreciated.

 

[thebigyellowtruck]

the only way to test without wires is to have the cap off and check to see if there is spark between the points. some mags have a window in the cap to see the spark so you dont have to pull the cap. If the tractor is being turned over you should be able to see a spark between the points. you also need to make sure that you have solid core wires. try replacing the condenser and points. A NAPA auto parts should be able to match up those parts. If that doesnt work you can always send your mag to be fixed.

there is a guy in Monroe Michigan that does great work on mags. maybe you could send it to him if you cant fix it yourself.

ROGERS EQUIPMENT CO.
6506 N Monroe St
Monroe, MI 48162
(734) 241-9580

 

[mrkwpatton]

Awesome I'll try napa... Is there any alignment that needs to be done when reinstalling the cap?

 

[John T]

You say its a Magneto (versus a battery powered ignition) so I'll take you at your word. A Mag requires no battery power to operate it and some mags have a wire attached which can serve as a kill switch. Some B's used a Wico XB battery powered distributor ignition thats NOT a Magneto mind you...

Theres plenty of ways to test for a spark without using HV plug wires.

If its a Wico X Mag you can remove the cap and use a piece of regular wire or paper clip etc wired to the mags metal case with other end about 1/8 inch away from the coils little side output HV terminal and turn the engine over and each time the mag snaps/impulses (every 180 of crank/flywheel revolutions) a spark should jump that gap.

If its a Wico C mag you can use regular wire ran out of the top caps HV outlet and have its other end to within 1/8 inch or so from the mags metal case and each time (each 180 of flywheel) the mag snaps/impulses a spark should jump that gap.

For the mag to spark at cranking speed the impulse assembly needs to be working and if so it makes a loud sharp SNAP each 180 of flywheel/crank revolution. No impulse working = no spark.

Common problems are points burned or corroded or not gapped properly.

John T

 

[thebigyellowtruck]

the cap should only be able to go on one way. at least that is how my wico magneto is. just make sure not to mix up the plug wires. otherwise the tractor will fire out of time.

 

[John T]

The cap only goes on one way with the Wico X, be sure to read my post above to tell how to test for a spark without using plug wires, just looking for sparking points isnt all that informative, you want to really be able to see if theres a high voltage spark available at the coil, thats whats needed to be able to eventually fire the plugs.

John T

 

[mrkwpatton]

Thanks John for all your help. It is a Wico x mag so I don't believe it has that option of hooking up a kill switch. I'll try testing for spark tonight with you instructions.

 

[El Toro]

If you have a mag there's usually a kill switch that will ground out the points so the engine quits running. Hal
PS: Here's an old Wico mag with a kill switch.

 

[John T]

Some X mags had the kill stud/terminal out throught the case like mine shown, others did not.

FYI sparking points DOES NOT MEAN THE MAG IS PRODUCING ANY HV SPARK (many coil problems are in the HV secondary winding), it ONLY means the coils primary circuit is continuous and conducting current

John T

John Ts Wico X Mag with kill switch stud

 

[greygoat]

Wico Magneto condenser: NAPA #WI-200
Contact set,(points), NAPA # CS-2201
For Wico XH mags on JohnDeere and Wisconsin
2 cylinder engines.
NOTE: A "New" NAPA parts book may not show these
numbers, (or any magneto parts) but the counter
man can "look them up" on the computer!

 

[thebigyellowtruck]

i have a wico model x on my allis wd. there is a stud that a wire hooks to for the kill switch

 

[Billy Shafer]

A good plug wire will work for testing. If your really brave stick your finger on the cap where the wire goes.