MTFCA Forum

Here are photos of the starter switch for my 1927 coupe. What should I do to it, if anything? Is there a way to test it before installing it in the car?

I assume the non-metallic washers next to the base are important and probably should be replaced.

What happens if a switch shorts out?

Yes you need the fiber washers between the base and the nut. The type you have is easy to take apart to check the contacts. They get pitted over time, and can be cleaned up to make better contact. Darryl

When you take off the cap by removing those two screws you'll find fiber insulation washers on both sides of the terminal posts.

Plus, a very important small fiber washer that insulates the 'hole' in the foot switch plate. That one is shown at the base of the post threads in the photo below. You can find suitable replacements at a good hardware store.

Be sure all are in good condition.

After replacing the insulating washers in my switch I used a wide flat file to make the two contact surfaces in the same plane. My contacts were tilted slightly and filing helped to prevent arc locations. There are several leaves that press against contacts when the button was pushed. I cleaned mine and rearranged them to put the leaves with the smallest arch on the outside. When I removed them originally, the flatter leaves were on the top and were not carrying current. I had not planned to remove the leaves but my switch flew apart when I tried to remove the starter switch's extension cap. Luckily, I found all of the parts in my cluttered shop.

These switch’s are pretty simple to check out. Chances are the fiber washers are still good. Remove the 2 screws and you can readily see if they are still good and intact. I wouldn’t change them if they didn’t need it. Good luck.

Here are close-ups of the inside of my switch. Comments?

Looks rebuildable to me.
Re insulate contacts with new hard fiber washers. . Turn the contacts for best contact area. Clean all the contact areas. A little silicone grease on contact areas.

I commented about the reliability of the so-called repro starter switches and their issues. I agree that it looks okay as is or an update with new insulators. However my "safety" preference is a starter solenoid. You can use the the old switch to activate the solenoid keeping things looking original or or a starter button if you don't care or doing a speedster.

Yours looks pretty good. I would align the contacts, and clean them up real good. I had a problem with one of those I wanted to use on my 4925. It was perfect, and I put the switch on with the extension, and it wouldn't go through the seat riser plate far enough.
So, I had to use a NORS replacement I had of the later design.