Starter switch question

[Rene R]

A month or so ago I went to start up my 28 Fordor and the switch stuck, causing the starter motor (and hence the engine) to keep turning over. Without a battery cut-off switch I was in a bind, but I managed to free it up by pulling up on the starter rod and unsticking it. After that I put in a battery cut-off...

All has been fine until a couple of days ago. The switch stuck again, only this time I couldn't free it up by pulling on the rod. It simply flopped around. Fortunately I had put in the cut-off and so I shut down the battery right away. The motor wasn't turning, but the switch remained stuck.

I went ahead and ordered a new switch and gasket and am eagerly awaiting its arrival.

Just now I removed the old switch in anticipation of putting in the new one soon. For the life of me I cannot figure out how that old switch could have gotten stuck in the powered position. It is, after all, a pretty simple design, with a very strong copper piece acting as both contact and spring.

Clearly it wasn't merely a short-circuit due to corrosion or something else or the rod wouldn't have had all that play when I tried to free it up. But I can't see anything at all that could have caused it to stick. Now that it's removed, and the contact/spring is pushing against the starter rod attachment, it's quite rigid. Not much play there at all.

Any thoughts from the experts out there? I'm definitely not a mechanic so I have no experience to fall back on. But I know enough about basic electrical circuitry to seriously question how this could have happened.

Also, the copper contact on top of the starter motor has a couple of very deep and large pits. I've thoroughly wire brushed it clean, should I be concerned that the surface is not totally smooth?

[Kurt in NJ]

If the contact on the starter is dirty, or too damaged that the contact area is small there will be high heat generated causing welding of the contacts.

The post on the starter can be filed flat ---just file till it is mostly smoothed, a few small pocks are ok.

A weak battery will have a lower cranking voltage, the starter will want more amps --this can also cause welding of the contacts.

Some of the repro spring contacts are weak also.

[hardtimes]

Rene,
This has been discussed/rehashed in previous threads. I'm betting that you have repop switch on your starter. If so, that's your problem. Your best answer would be AN ORIGINAL switch. But, in my experience, if you must use a repop..coat the contact areas with 'dielectric' grease. The repop junk copper spring in the switch is NOT close to the quality of the original Henry equipment. After cleaning/rebending my repop switch contacts/spring, and applying the dielectric grease...no recurrance YET! Looking for an original switch if anyone has such to sell.
BTW..good move on the master shutoff switch installation, as this type incident is ANOTHER good reason for such equipment!

[Rene R]

Thanks for that input. That definitely makes sense. I've filled down the contact on the starter though the pitting is so deep I couldn't remove it 100%. But it's a clean, smooth surface now, and I can certainly see how irregular and corroded the contact inside the switch has become -- along with how brittle the paper insulation is.

Once I get it I will compare the new (repro) switch to the the one I have. If necessary I'll clean and put my current copper spring/contact into the new switch, if it appears that it's sturdier.

I don't quite understand the suggestion about coating the surfaces with dielectric grease, however. From everything I've found online, this is non-conductive and not recommended to to directly onto contact surfaces:

Dielectric grease is a nonconductive grease. As such, it does not enhance the flow of electrical current. Thus electrical conductors should not be coated with dielectric grease prior to being mated. Dielectric grease is, however, often applied to electrical connectors, particularly those containing rubber gaskets, as a means of lubricating and sealing rubber portions of the connector.
The widest use of dielectric grease is in high-voltage connections associated with spark plugs. The grease is applied to the rubber boot of the plug wire. This helps the rubber boot slide onto the ceramic insulator of the plug. The grease also acts to seal the rubber boot, while at the same time preventing the rubber from becoming stuck to the ceramic. Generally spark plugs are located in areas of high temperature, and the grease is formulated to withstand the temperature range expected.
Another common use of dielectric grease is on the rubber mating surfaces or gaskets of multi-pin electrical connectors used in automotive and marine engines. The grease again acts as a lubricant and a sealant on the nonconductive mating surfaces of the connector. It is not recommended to be applied to the actual electrical conductive contacts of the connector because it could interfere with the electrical signals passing through the connector.

[hardtimes]

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Rene,
Yup, whatever it takes,eh! I've been using this dielectric grease(which is NOT really a grease at all..I'm told)on everything electrical connection that you could/would ever think of..with great satisfaction! The 'proof' is in the pudding' as they say, as I've never revisited a connection that was corroded/oxidized , which is fairly common with electrical connections and never had a connection to be hard to get apart and/or back together...as connections are prone to be. This incluces no oxidation of soldered connections also. Hey, your mileage may differ!

BTW...have read here/ole barn about guys having trouble with (mainly) repop light switches working hard / not working/etc. Since original light switch could not be located at the time, upon assembly.....yup, used dielectric grease on contacts of repop. Uuuh, works like greased pig feces!!