TN 65 keeps blowing fuse when you try to start it

   / TN 65 keeps blowing fuse when you try to start it #1  

Robert_in_NY

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Silver Creek, NY
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Case-IH Farmall 45A, Kubota M8540 Narrow, New Holland TN 65, Bobcat 331, Ford 1920, 1952 John Deere M, Allis Chalmers B, Bombardier Traxter XT, Massey Harris 81RC and a John Deere 3300 combine, Cub Cadet GT1554
Ok, this is a problem for me as I need this tractor. My TN 65 standard started giving us problems about a month ago where it wouldn't start. When you turned the key to start nothing would happen but the dash lights come on. The third try and it would turn over and start. Then it starting blowing the 5 amp fuse, replace it and it would start and work fine. Then it blew multiple fuses before it started. Now it won't start and keeps blowing fuses. I have to cross the terminals on the starter in order to get the tractor to start. I was hoping to put this off till I was done with tillage and planting (a couple more weeks) but I do not want to have to start this tractor this way. Twice was enough.

When I crossed the terminals on the starter it would just spin but not engaged the first few tries then it engaged and the tractor started. I am wondering if the starter is the problem but before I pull it and have it tested I wanted to ask you guys who most likely know a lot more then I do about this type of problem. Thanks.
 
   / TN 65 keeps blowing fuse when you try to start it #2  
Putting a screwdriver across the two main terminals will only make the armature spin . You need to also touch the small wire terminal to make the solenoid throw the Bendix into mesh with the flywheel . I think you just didn't have the screwdriver quite in the right spot the first time and the starter is fine . As for the fuses blowing , i would have a real good look around the wiring loom as it may be rubbed or pinched somewhere .
 
   / TN 65 keeps blowing fuse when you try to start it
  • Thread Starter
#3  
I will look the wires over real good as I have to pull the lower dash panels to properly fix the throttle lever (it keeps loosening up and is a pain to tighten).

I only had to touch the two main terminals on this starter to get it to start. I touched it in the same place each time and had the same results both times I had to try it. It had to do this in the past once and it started up fine with no problems which is why I have been thinking the starter may be the culprit. Regardless I am going to inspect the wires closer as soon as the wind calms down. I have my barn filled with other equipment being worked on so the TN is parked outside right now:(
 
   / TN 65 keeps blowing fuse when you try to start it #4  
Without knowing which fuse is blowing, (or what circuit it powers) it is impossible to offer meaningful help.
Iron Horse is correct about jumpering the two large solenoid connections; that should NOT make the tractor crank over. You should be able to jum the starter by crossing the battery post of the solenoid and the small solenoid trigger wire, leaving the starter motor lead alone.
 
   / TN 65 keeps blowing fuse when you try to start it #5  
Hmm , that does not sound good . Does your solenoid have 3 terminals ? 1 going to battery , 1 going to the back of the starter and 1 little one ? The little wire is the solenoid exciter wire . If yours is like this , it would indicate the Bendix is already in mesh and that the starter is spinning while the engine is running . Putting power across the battery wire to the little wire should engage the Bendix which in turn closes the loop across the two large terminals internally which in turn energises the armature .

On edit , i see Rick has also answered your question while i was slowwww typing . Just a thought , if the Bendix is not being held in mesh mechanically , ie. bent shaft etc . You may try turning the ignition on so the dash lights are on and check to see if the solenoid gets warm after a while . It may be being energised before the key is turned fully to the start position .
 
   / TN 65 keeps blowing fuse when you try to start it #6  
Don't know anything about a TN65... but could it be a starter relay problem? I've had relays do funny things when they get moisture in them.
 
   / TN 65 keeps blowing fuse when you try to start it
  • Thread Starter
#7  
Without knowing which fuse is blowing, (or what circuit it powers) it is impossible to offer meaningful help.
Iron Horse is correct about jumpering the two large solenoid connections; that should NOT make the tractor crank over. You should be able to jum the starter by crossing the battery post of the solenoid and the small solenoid trigger wire, leaving the starter motor lead alone.

According to my manual it is the "Starter Safety Circuit".

The solenoid trigger wire is still hooked up to the starter. All I had to do was cross the two large connectors. Could this be a problem if it allows me to do it or is it defying the laws of physics or something???
 
   / TN 65 keeps blowing fuse when you try to start it #8  
I also do not know anything about a TN 65. However if the starter has an inertia drive Bendix, it will engage when the starter motor turns and does not need the extra circuit that pulls the starter drive into the flywheel ring gear. This sounds like the situation that the OP is describing.
 
   / TN 65 keeps blowing fuse when you try to start it
  • Thread Starter
#9  
Here is where I jump across to start the tractor. It isn't a great picture as it was dark, raining and very windy. It is a Bosch Starter but hopefully the crude arrows I drew pointing to where I jump across will be enough for you guys to see what I am dealing with and potentially advise me. Thanks

505081723-1.jpg
 
   / TN 65 keeps blowing fuse when you try to start it #10  
Sounds like a grounding problem. The back-feed is glowing the lights and blowing the fuse. Also commonly seen on trailer light hookups when you loose the ground thru the ball.
 
 
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