B John Deere starter

Have a 48 B starter is an issue. Tried a couple different switches on it not making contact thru switch. Power down to starter checked w meter. Leave switch off starter touch contact on starter w cable end spins fine turns engine over. Put switch back on starter push button by hand to full travel nothing. Is there a spec on that starter contact for height? Are some of those switches junk?

those were junk when new

I cant say for sure not being there, but I have seen many of the big copper starter post (where switch engages) worn down too low or carbon or pitted to the point even a good switch fails to make good contact. Of course as you're already aware the switch has to push down hard and far and deep enough to make good contact.

In any related cases I advise people to remove, clean n wire brush and re attach each and every battery and starter and ground cables and a ground to any thin wimpy rusty sheet metal part can cause a starting problem, I like a ground cable ran down to heavy solid clean shiny metal near the starter.. Make sure the battery is full charged and in good shape also. A loose or burned or corroded resistive connection anywhere in the circuit can cause excess line voltage drop causing poor starter performance.

HOWEVER if as you describe it cranks okay if jumped direct to the starters big side copper post/stud but NOT otherwise sounds more like a switch failure (not deep enough hard solid contact) or the starter post has a problem and they can be replaced if worn too low or damaged...I have cleaned and smoothed them down making them work again.

John T

(quoted from post at 07:40:07 05/19/20) Have a 48 B starter is an issue. Tried a couple different switches on it not making contact thru switch. Power down to starter checked w meter. Leave switch off starter touch contact on starter w cable end spins fine turns engine over. Put switch back on starter push button by hand to full travel nothing. Is there a spec on that starter contact for height? Are some of those switches junk?

Click to expand...

As the others said, that was not a great idea when new, and now with parts from "The Land of Almost Right" it's nearly a hopeless cause.

Best you can you is look for a new old stock genuine Delco switch, there's usually some on fleabay. I shop there for NOS points, condensers, caps, and rotors, as well.

As a workaround to use what you have IF the starter stud is not too badly eaten away, it works to slot the mounting screw holes in the useless starter switch a little to move it in the direction of the "drive end" casting, this works to make the copper contact plate contact the stud in the starter "belly" sooner and harder.

I've done this several times, with success.

There may be an interferance issue if the rough cast edge of the "snout" flange is in the way of the repositioned switch sitting down again the starter "belly", that can easily be taken care of with a grinder.

Also, if the stud in the new switch is held in place with a nut (rather than being crimped in place as some of the new JUNK is) you can take the stud out of the switch and add a washer with a small O.D. that fits the stud between the stud and the switch body, moving the contact area on the stud slightly towards the copper contact plate.

Be sure to keep the insulating washers and sleeve in place so the stud doesn't short to the (grounded) switch body.

you have mail.