john deere M ignition problem

farkle

New User
Was having trouble with only running on one cylinder, changed plugs and points. now is backfiring out exhaust blowing fire and sparks and seems extremely hot. when checking the points for spark I noticed its also sparking where the distributor shaft runs on points to open and close them. (its jumping past the little nylon bushing that its supposed to ride on ).any advice would be appreciated.
 
Is number one plug wire on Number one Plug &
is the wire in number one position on the cap?
 
Sometimes the spring on the points is shorting, the normal current path TO GROUND is from the wiring terminal where the condensor and the wire from coil (via the distributors side pass thru insulated bushing) is attached, then when points are closed to the distributor case/frame ground. Make sure all the little wires from condensor,,,,,,,to coil via pass thru,,,,are good and not shorted, then be sure when the points are open THERES NO TO GROUND PATH from the little wiring terminal. Both the coil wire and condensor are only grounded out when the points are closed. The condensor, to straight DC, should show an open circuit to ground ya know otherise its bad/shorted out.

With IGN ON, put a DC test lamp on the coils output (or where dist side terminal is) and with engine slowly turned over, it should be ON when points are open but OFF when closed

As already posted the cap and rotor tip needs to be in correct time with the cap so when the coil fires the tip is lined up with the correct cap pickup/terminal. The coils fires when the points break open and at that time the rotor tip needs to be lined up with the right cap pickup.

John T
 
Perhaps I'm leaving only breadcrumbs that might lead to nowhere, but it seems to me that the distributor "T" drive can be inserted 180 degrees from where it should be in the drive out of the top of the oil pump shaft. Then too, some M & MT distributors have four breaker point opening lobes on the shaft, some have two. Could either of these anomalies be figuring into the fun you're having?
 
Dubuques are NOT my cup o tea so NO WARRANTY but I think those drives have an offset so its impossible to install them 180 out WHERES M MAN WHEN WE NEED HIM

John T
 
My guess is when you tightned the nut holding the condensor wire you let it move and the points spring got pushed down to where it is touching. It has to stay straight.

Lets do this over. Better NAPA or Deere points. Gap at 19. Dist terminal will be at about 5 looking straight on. Dist posts will be about 5 minutes till three. Front post to front plug. Fire her up and put a timing light on front plug wire. Should see SPARK centered in the window at full throttle. At idle it should drop back to TC (close). If it doesn't drop back when the speed drops the advance is stuck.

John is correct about the dist. The only way to get it 180 out is to drop the oil pump or change the drive lug on the bottom of the dist.
 
Thanks guys, had a little time today to mess with it. You were right about the spring and condenser wires shorting out,( due to a cracked insulator). so I got the sparking on the shaft fixed. now with the cap off I can not get a consistent spark out of points when cranking it over.I get a few weak sparks then quits. when I install cap, im getting a unconsistent spark on the plugs and will not fire when trying to start it. could it be the coil ? thanks.
 

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