Kubota L3400 HST did not start after stalling

[Hai]

I turned off the tractor, went to do some other chores, came back and could not restart the tractor. One click sound. My neighbor, who has a Kubota L3130, checked the safety switch under the seat but that was not it. The switch has been disabled by the previous owner. Finally he tapped on the starter with the hammer, it started.
Then two days ago I was digging/scooping a dirt mound with my Kubota L3400 HST front end loader. I probably had the loader angled down too deep, the front end of the tractor raised up, and the tractor stalled immediately. I could not restart the tractor. The instrument lights were on as usual when the key was turned to the on position. When the key was to turned to the start position, only one click sound. The tractor did not start, just the click sound each time the key was turned to start. Finally I tapped on the starter with the hammer like my neighbor did before, it started.
It started fine the last several times since then.
But this problem really bothers me. I need this tractor to be reliable to start every time. Is it the starter? or the safety switch under the seat? or the neutral position of the forward-reverse speed paddle?
Where should I start? Many thanks in advance.

 

[Baby Grand]

Sounds like the solenoid on the starter is sticking. May also be a bad lead-in chamfer on the ring gear that causes the starter pinion to hang before it closes the switch to energize the starter motor.

 

[grainger12002]

always a good idea to check battery connections at the battery, starter and ground connections, get em clean, see if it helps


From CT

 

[Hai]

That is what I plan to do next after the rain. It will rain here for the next 2 days or so.

 

[Hai]

Thanks Baby Grand.
Solenoid sticking - can it be cleaned?
Bad lead-in.... - you mean the trigger wire coming into the starter? I noticed that this wire tip was not real clean. What is the best cleaning fluid for this? I do not want to use WD40, which would make the connection more loose.

 

[Citydude]

You can pour Coke (cola) on dirty battery cables and battery posts to clean the gunk off. Dissolves it on contact.

 

[LD1]

I vote bad solenoid in the starter also. Pretty much confirms that when you tap on it, she fires.

 

[jimmysisson]

Or hung brushes in the starter

Jim

 

[Baby Grand]

Thanks Baby Grand.
Solenoid sticking - can it be cleaned?
Bad lead-in.... - you mean the trigger wire coming into the starter? I noticed that this wire tip was not real clean. What is the best cleaning fluid for this? I do not want to use WD40, which would make the connection more loose.

Not quite, Hai.
On most starters, the ring gear on the flywheel and the pinion gear on the starter are not in mesh, so the engine doesn't spin the starter while it's being run. But when you first start the engine the solenoid pushes the pinion into mesh with the ring gear, until the engine starts running and you let the key go, at which point the pinion drops back out of mesh. To allow the pinion to move into mesh with the ring gear, both gears often have the sides of their teeh chamfered so they won't hang up.

Starter solenoid - Wikipedia, the free encyclopedia

Diagnose Starter & Alternator Problems

 

[Hai]

I have a better understanding of how the solenoid and starter work now. Many thanks to you and your suggestions. When it's sunny, I'll start checking from the battery to the solenoid, etc. using the multi voltage meter.