Farmall starting circuit

1944 farmall m 6 volt- wont crank, had starter rebuilt, new cables, new battery. Cleaned ground reAl good, no crank still, however im getting continuity from the hot post on starter to ground, along with other hot terminals to ground had continuity. Wouldn't it be a short? Bench test starter and it cranks no problem!

Can you turn the engine with the starter removed by prying on the flywheel or using the crank

Engine is loose

(quoted from post at 22:13:45 06/19/13) 1944 farmall m 6 volt- wont crank, had starter rebuilt, new cables, new battery. Cleaned ground reAl good, no crank still, however im getting continuity from the hot post on starter to ground, along with other hot terminals to ground had continuity. Wouldn't it be a short? Bench test starter and it cranks no problem!

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The hot post on the starter will have continuity to ground through the starter. The internal resistance of the starter is very low so it would appear to be almost a dead short. That is why the current draw is so high when voltage is applied to the starter cable. This continuity should exist all the way to the starter side if the starter switch. The other side of the starter switch back to the battery should not have continuity to ground unless there is another switch left on. If either the ignition switch or the light switch were on they would provide a path to ground.

Instead of checking continuity to ground it will be much easier to find your problem bu checking voltage drop under load across each part of the system. There should be no drop along a cable. A connection should have no more than .1 volt. A switch should have no more than .2 volts drop.

With all that you have done I would take a close look at the starter switch. Check the voltage drop across the two terminals while trying to crank the engine.

Some starter switches are no good, some are good but do not touch the "hot post" when used. There are several types of starter switches on Ms. If it is a push button on the light bar, or down low for foot or rod push, check that there is voltage getting to the starter side of that switch. If it is a starter mounted switch, the internal moving part may not touch the hot stud on the starter. Use a thin rat tail or chain saw file to elongate the holes to allow closer contact. Jim

If the starter is good (rebuilt right) and all the cables n grounds n connections are good (what you indicated) ID GUESS A SWITCH PROBLEM......... Try using jumper cables to jump around by passing the switch (IF its where you can get at it and a push type pedestal series switch NOT a saddle mount on starter)........

With a Volt meter with one lead to frame, there should be hot battery voltage on the input side of switch (from battery) and, of course, with switch depressed then and only then voltage on output side of switch to starter. An OHM Meter will show near 0 ohms on starter post.

If when you depress the switch the lights dont dim way down nor battery voltage drop much Id suspect the switch may have a problem, but if the lights dim way down and battery voltage drops drastically, Id say the switch is good but theres a starter electrical or mechanical (stuck jammed to flywheels ring gear) problem.

Those big copper lookin contacts inside a start switch can get all burned carboned and pitted and fail pretty easy. If its a saddle mount direct on starter switch remove it and the big copper post on starter can get burned carboned pitted and worn down too low. I have seen cases where the mechanical push down linkage to a saddle mount on starter switch isnt right so the plunger dont get pushed all the way down as it needs.

Nuff said

John T