solenoid

[oldford2]

Nice day here in western MA and snow forecast for the weekend. So thought I would dig out the 46 and take a ride. Has not run in over a week. Put the charger on early and after a couple of hours the green light came on indicating full charge. Turned on my electric pump for 20 seconds or so. Then pulled the choke and it cranked and fired briefly No start. So I cranked it a few more times for 10 or more turns and nothing. When I let up on the starter button the engine was still turning slowly and when I turned off the ignition it still was slowly turning over. I have a master switch so killed the power. The starter solenoid on my test stand would stick some times and I would tap it with a small hammer. So I think I will replace the solenoid. I called Joe's and he will mail it tomorrow. (Great guy)
So, here is my question... Could the contacts in a solenoid get corroded and not send full current to the starter?
Thanks
John

 

[Lawson Cox]

Possible, but I doubt it.

 

[r_reed]

easiest way to find out would be to bypass the solenoid: maybe use one of the jumper cable to connect around the battery terminal to the starter terminal on the solenoid. anyone one see any risks to this?

 

[51 MERC-CT]

There can be a buildup of residue caused by time and the constant arcing at the contacts.
If it could be taken apart those contacts could be cleaned.

 

[Mmeader]

I would say yes, if there getting corroded , or heating up and pitting, that's adding resistance to the current path to your starter, imo

 

[V8COOPMAN]

Possible, but I doubt it.

I always wondered why some people answer questions......when they don't know the answer. Here are two perfect examples of a solenoid's contacts becoming corroded, burned and generally beat-to-hell, because of the continued arcing every time the solenoid goes through a cycle and the contacts "make", or "break". I remember as a younger, broke kid in the '60s with mostly Chevys, when the worn-out solenoid began "clicking" with regularity instead of turning the starter, all you had to do was go inside and 'flip' that big, copper washer (which was all burned, pitted and corroded) over to it's other fresh, smooth side and you were good to go for at least another 5,000 'starts'! YWB

 

[ford38v8]

Coop, You ol' devil. Ya caught 'em with their pants down!

 

[big job]

Absolutely yes... same thing happened to me. John nothing to loose take it apart
I bet it looks like asphalt pavememt. I too got one from the 'great Joes' starts
like its got 12 volts now..sam

 

[fortyonerag]

Way back when I was a green and simple auto elec, it was not uncommon to see bad terminals in solenoids when you were rebuilding starters.

Slow cranking suggests you have a corrosion induced voltage drop in the solenoid (it would be getting pretty hot too). It being stuck, i.e. cranking without the key, suggests that the terminals may have welded.

Buuuut, while you're at it, check that the starter wire hasn't fallen off the starter button and is earthing and operating your solenoid - working the starter.

 

[oldford2]

I always wondered why some people answer questions......when they don't know the answer. Here are two perfect examples of a solenoid's contacts becoming corroded, burned and generally beat-to-hell, because of the continued arcing every time the solenoid goes through a cycle and the contacts "make", or "break". I remember as a younger, broke kid in the '60s with mostly Chevys, when the worn-out solenoid began "clicking" with regularity instead of turning the starter, all you had to do was go inside and 'flip' that big, copper washer (which was all burned, pitted and corroded) over to it's other fresh, smooth side and you were good to go for at least another 5,000 'starts'! YWB

Great!! Thanks to all especially Coop for the pictures. Now I have a project and optimistic that I can get things working.
I will follow up with what I found in the old solenoid And how the new one works.
Thanks again
John

 

[Frank Miller]

Upon starting an electric motor is a dead short. When it starts turning the current flow is reduced. This switch sees the full battery current upon contact. Because it is 6 or 12 volts there will not be a very big arc but there is one and it corrodes the contacts. I suppose if a coil could go weak it would make for a bad connection resulting in corrosion. If you do not have an infrared thermometer they are worth the investment. Any poor electrical connection will show up as heat. It may only be a few degrees difference but that is an indicator to a problem. Under normal conditions no switch or cable should get hot. The solenoid cable will produce a little heat but that is all.

 

[51 MERC-CT]

Great!! Thanks to all especially Coop for the pictures. Now I have a project and optimistic that I can get things working.
I will follow up with what I found in the old solenoid And how the new one works.
Thanks again
John

On the Ford solenoid you have to disengage or grind off the retaining lip to gain access to the internals.

 

[V8COOPMAN]

Great!! Thanks to all especially Coop for the pictures. Now I have a project and optimistic that I can get things working.
I will follow up with what I found in the old solenoid And how the new one works.
Thanks again
John

And here is a picture of the "innards" of John's sickly solenoid. No doubt that it WAS obviously 'hurting' at the point where the contacts "CONTACT" each other. Good troubleshooting, John! DD

 

[oldford2]

Coop,
Thanks for posting. I am having trouble sending pictures this week.
That shiny spot on the left was a built up "dimple" . 1/16" dia and .043 high. So the copper disc could not sit flat on the surface and apparently all the current went thru that tiny bump. No wonder it turned over slowly!
Thanks to all. I learned something new. (and so did Lawson) The problem is that at 82 I forget 2 things for every new one learned.
John