MTFCA Forum

So I have a starter switch on my 26. It's the kind that has the top part with the button held on with two screws. My question is how are the two studs that the battery cable attaches to not grounded together by the bracket that hols them? Should there be a rubber washer insulating the studs? I had a rubber washer on one of the studs.

Originally they used a hard insulating rubber like material for the insulators for each stud.
Take it apart and you can get a better idea how it’s supposed to work. I can’t remember the name of what it’s made from but it works pretty well. It’s fairly simple how it works once you check it out on the inside. The studs are insulated from the metal case.

John kuehn wrote: ↑

Sun Jul 25, 2021 11:07 pm

Originally they used a hard insulating rubber like material for the insulators for each stud.
Take it apart and you can get a better idea how it’s supposed to work. I can’t remember the name of what it’s made from but it works pretty well. It’s fairly simple how it works once you check it out on the inside. The studs are insulated from the metal case.

Fiber washers. Usually a thin fiber ring around the studs & 1fiber on top & bottom. Thin fiber can be substituted with o-rings.

Not sure if you have a switch like the ones pictured below. If its different a picture would help. But like all the others the insulation method would be the same

Originals had 3 fibre washers at each stud. One goes under the flat head of the contact. A second goes around the stud to isolate the stud from the bracket. The O ring suggested in a previous post would achieve this. Then a third fibre washer goes on between the bracket and the nut. Hard rubber would not do, as these studs/bolts need to be really tight. It helps if you have a thinned down open end wrench to hold this nut when you are fitting the cables, which also need to be tight. As you add tension to the nut, the thinned down wrench allows you to maintain the original orientation of the stud.
Hope this helps.
Allan from down under.

So this is the type I have. I can see the fiber around the contact (stud). This makes sense now. One of the rubber washers that was used under the switch was broken.