ignition problem

WV Farmall · Jun 3, 2012

I have two questions. On my farmall M the previous owner converted it to 12 volt system but he used a positive ground alternator. Has anyone run into this and if so where could I get a wiring diagram for this system? Other question, I changed point set on the M now I can not get spark to plugs. What might be the problem? Even put old set back in and could not get spark. Points are opening and closing and there is voltage to the distributer?

Janicholson · Jun 3, 2012

No issue with the polarity. It is the same as negative ground. The only difference is the battery polarity is POS ground, and the coil should be Positive to the distributor.
We cannot recommend a wiring diagram unless you identify the alternator, a picture will work, as will numbers and stamped info from the alternator. If we supplied one it would not be correct 90% of the time.
The lead from the points to the outside of the distributor is likely to be shorting to ground. The placement of the points connection, and condenser lead must be isolated from the case where it passes through. New points must be cleaned to assure they conduct. Gap is .020". Jim

WV Farmall · Jun 3, 2012

The alternator is an AC Delco. The only info on the alternator is 12 Volt Pos. Grnd. 6o amp. Looks to be a model 10SI.

WV Farmall · Jun 3, 2012

I need to correct myself it is a Delco Remy alternator not an AC Delco.

Brownie 450 · Jun 3, 2012

Really dumb question here---are you setting the point gap on the high lobe of the distributor shaft?
The reason I ask, is the wife's cousin set his point gap on the low part of the dist. shaft. Points would never close.

WV Farmall · Jun 3, 2012

The only dumb question is the one that is not asked. The points are set on the high lobe on the shaft and are opening and closing but not getting any spark to plugs.

roger hall · Jun 3, 2012

check for a rotor button

David G · Jun 3, 2012

Good point, you did put the rotor back in?

Janicholson · Jun 3, 2012

If it is a Delco 10SI, it will jhave an edge mounted two prong connector for sensing bat voltage (terminal 2), and a excite circuit (connected to terminal 1) the #2 terminal can be connected directly to the big terminal with a short piece of wire and terminal ends.
The #1 terminal should be connected to the ignition switch through a 10 ohm 10 watt resistor, or through a clearance marker light bulb, or through a diode, (the diode should have its band facing the ignition switch, this keeps alternator excite current from runnung the ignition, which keeps it running even when shut off. All of these will do the same job, so it is your choice. the big #10 output wire should go to the load side of the amp meter. (not the battery side. Jim

WV Farmall · Jun 4, 2012

Just wanted to follow up on the problem. I filed points as was suggested and and made sure there was nothing grounded, hit the starter and she fired right up. Thanks to everyone for the tips!!

Janicholson · Jun 4, 2012

Thanks we always need to hear back what worked. Jim

ignition problem

WV Farmall

Member

Janicholson

Well-known Member

WV Farmall

Member

WV Farmall

Member

Brownie 450

Member

WV Farmall

Member

roger hall

Member

David G

Well-known Member

Janicholson

Well-known Member

WV Farmall

Member

Janicholson

Well-known Member

Similar threads