+ or - ground and distrubuter replacement on 641 w

I am planning on replacing the distributor with a petronix igniter. I am hoping it will be more reliable and less maintenance. I also replaced the coil.

When I called to get the right igniter for my 641 ford workmaster I was asked is it positive or negative ground. So I looked in the manual and it said positive ground. Well I have all ways hooked the negative to the frame and the positive to the wiring harness. I didn’t now batteries were ever hooked up any differently. Have I had my battery in backwards all this time? Will it run either way? Also the old coil had terminals labeled battery and distrubuter but the new one says + and -. I hooked the positive terminal to the wiring harness and the negative terminal to the distrubuter. Does that sound correct?

Thanks Dave

FIRST NOTE OF CAUTION; Make sure the elec ignition matches however your tractor is wired (Pos or Neg ground) or you can fry it !!!!! !!

Q: Have I had my battery in backwards all this time?

A: YES if she came from the factory Positive ground as you indicate

Q: Will it run either way?

A: YES it can run at EITHER polarity and can still charge at EITHER POLARITY (provided genny was correctly polarized and VR is suitable for the ground which many are) BUTTTTT TTTTT T if the coil is used at reverse polarity, although it still runs, the coil is less efficient (may run a tad warmer) and the spark a bit weaker. The coil should match the tractors polarity, if its POS ground the coils + lead wires to the distributor, while if NEG ground the coils - wires to the distributor.

Q: Also the old coil had terminals labeled battery and distrubuter but the new one says + and -. I hooked the positive terminal to the wiring harness and the negative terminal to the distrubuter. Does that sound correct?

A: See above, if youre at Neg ground, then the coils - (distributor) wires to distributor but if youre at Pos ground, the coils + (Battery) wires to distributor

On coils labeled Battery + and Distributor - intended for use on Neg ground tractors, thats exactly what it means, the + Battery is the hot feed wire down from the switch while the - Distributor terminal wires to the distributor

ENGINEERING NOTE: to get the most bang for the buck that elec switch has to offer, I highly recommend you couple n match it up with a high energy coil as recommended by the switch vendor. Even the old stock coil will give improved performance from use of an elec switch due to the faster more positive switching HOWEVER the elec switch can switch more current plus do it faster so it can be used to pump more energy into a high performace coil yielding more spark plug gap energy to better ignite the fuel. Its also important to have the switch rated to handle the current a high energy coil may require so be sure the vendor matches the switch rating for the coil you may use !!!!! !!!

John T retired electrical engineer

Dave

Thanks

Thanks Dave

An ammeter can be made to register correctly SIMPLY BY REVERSING ITS LEADS.

A bi metal heat type of fuel gauge will work REGARDLESS OF POLARITY cuz current still flows through it and heats up regardless which direction of current flow.

A galvo type of fuel gauge, however, IS POLARITY SENSITIVE and wouldnt work if mis wired.

Of course, a pure mechanical heat gauge isnt electrical and still works regardless, same as for a pure mechanical oil pressure gauge.

They sell switches for pos and neg ground systems, JUST BE SURE TO USE ONE TO MATCH YOUR TRACTORS POLARITY

John T