Starter motor runs continuously.

[native]

Was spreading manure last night and stopped to talk to my neighbor. I restarted the motor to continue working and noticed the starter continued to spin, though not engaged. I really needed to finish spreading (rain was coming) so I disconnected the positive cable to the battery (I have a quick disconnect on the battery)and finished. This evening I pulled the starter and removed the top cover with the rubber boot. The switch provides continuity only when switch is compressed from the inside. I believe this is the way it should function normally. The only thing I can figure is the solenoid stuck closed but ran out of time to check it this evening. Has anyone ever had this happen and did running the motor with positive cable disconnected from the battery harm anything in the elctrical system? Thanks in advance for any advice.

 

[Dandy Dave]

It sounds like you do have a stuck solenoid. Not the best thing to run the generator without a battery, but probably will be alright. I would replace the solenoid if it were mine. Dandy Dave!

 

[jack harmon]

believe it or not a very low battery will cause this.I have no clue as to why,but ive seen a hundred of them do it over the years.charge your battery good and it stops,I "THINK"(scary) that in the right conditions solenoid/relay acts sort of like a potential relay where it needs the back emf to kick out,cant verify that, but i dont understand what else could cause this.used to be a real problem years ago,starter would get hot enough to cause fires very quickly.

 

[Mike Farmer]

Not terribly unusual. If it continues to do this then ideally replace solenoid. Short term to avoid damage just briefly disconnect battery each time, when you reconnect the solenoid should not kick back in. Incidently it just may not ever do it again. MTF

 

[Mike Farmer]

Got my stupid head on. Switching off ignition should do the same thing as disconnecting the battery.(Unless of course your engine system is ignition controlled)MTF

 

[Dave Matt]

I"ve also had this happen when trying to start an engine with a low battery, especially in the winter - what seems to happen is that the low voltage causes the solenoid to throw the brass (copper?) plates in the solenoid switch together too slowly and they arc for a while as they"re coming together and then weld themselves together, so when current is removed from the solenoid, they remain welded and current still passes through them to the starter, keeping it spinning.

Dave

 

[native]

I removed the old solenoid and found a large crack in it. Replaced it with a new one and it started right up. I busted the old open and found a lot of corrosion where the contacts come together. I'm just wondering if the crack caused it to corrode, just old age or a combination. I suspect both. Thanks for all your help.