Farm Equipment - R 62 key switch failure, starter engaged

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R 62 key switch failure, starter engaged

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=197823
Printed Date: 24 Sep 2024 at 11:29pm
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Topic: R 62 key switch failure, starter engaged

Posted By: Leon B MO
Subject: R 62 key switch failure, starter engaged
Date Posted: 21 Oct 2023 at 9:32pm

This can only happen to me. Son was running in corn, smelt something. Stopped and found smoke coming from the bell housing area. Went back to shut off engine and the key switch would not stop engine even with key removed. He pulled the connection going to the inj pump to shut the engine down. The starter was to hot to touch. Pulled the starter, the gear and shaft were blue from heat. Installed a new starter and when we turned the key to the run position the engine started turning over. So we tested the key switch, all 3 terminals were hot in the run position. Install a generic key switch to get going. But when we reved up the 8.3, the volt meter went hard right. Tested, altenator putting out 19.9 volts. Took it off and replaced.

We are back running, new key switch, starter and altenator. 14ish amps.

So my question, could a bad key switch cause the starter to engage while in the field running and fry the alternator. It had been running for about 30 minutes before Curtis smelt something.

Leon B MO

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Uncle always said "Fill the back of the shovel and the front will take care of itself".

Replies:

Posted By: DrAllis
Date Posted: 21 Oct 2023 at 9:43pm

I don't think so. As soon as you shifted it out of neutral and into gear, the signal (if there was one) to the starter was cut off. It sounds like the starter relay (close to the starter) or starter solenoid itself that stuck "ON".

Posted By: Leon B MO
Date Posted: 21 Oct 2023 at 10:07pm

The neutral switch does work properly. I forgot about that. So as soon as it's put in gear, it would delete the key switch. So it was a starter solenoid issue. Trying to wrap my head around why the engine would not shut down with key out of ignition. Yes the starter would still be running but the fuel should be shut off?

Could a starter engage and run with the the engine and actually be overcharging the system??

Leon B MO

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Uncle always said "Fill the back of the shovel and the front will take care of itself".

Posted By: Ron(AB)
Date Posted: 22 Oct 2023 at 12:35am

What did the volt gauge say when this happened?

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405, 7000, 7050, 8050, 8070, L3, 2300 & 2600 disk

Posted By: DrAllis
Date Posted: 22 Oct 2023 at 1:36am

I said STARTER RELAY (close to starter) or the STARTER SOLENOID (on the starter). Two possibilities. High voltage from the alternator may have played a big part in this.

Posted By: jaybmiller
Date Posted: 22 Oct 2023 at 5:48am

For sure replace the starter solenoid. They're designed to pass 100s of amps but only for a few seconds. They also don't last forever. Contacts 'pit' over time and use.

Only 2 ways a starter will keep running.

1) 12volts applied to 'start' terminal on the solenoid

2) contact inside solenoid are shorted

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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)

Never burn your bridges, unless you can walk on water

Posted By: Amos
Date Posted: 22 Oct 2023 at 7:45am

I had my starter stay running after I started my R52 one time, it was the starter relay, as Doc said, I would change yours if I were you, cheap insurance it doesn't happen again, and I would guess it may have been in start position for longer than ever designed for after your excitement!

Posted By: Leon B MO
Date Posted: 22 Oct 2023 at 6:56pm

Doc, where exactly is the starter relay located? I will replace it also. We don't know what the volt meter was reading at the time he smelt somthing. He was trying to find the source of the smell. But after replacing starter and solenoid, the gauge was pegged and my meter read 19.9. After all this, we got her going again but today the pivot jackshaft outer bearing had been spinning on the shaft. Shaft is junk, will look for a replacement first thing in the morning.

Thanks all.

Leon b mo

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Uncle always said "Fill the back of the shovel and the front will take care of itself".

Posted By: DrAllis
Date Posted: 22 Oct 2023 at 7:02pm

Been a long time since I've been in the engine compartment of an R-62. It will be close to the starter and wired to the starter solenoid. It might be attached to the engine block or the frame the engine sits on.

Posted By: Les Kerf
Date Posted: 24 Oct 2023 at 8:42am

A DC motor being forced to spin becomes a generator producing un-regulated current. I wonder if this could have led to the damage to the alternator?