Fuse #2 Frustration (Class III Boomer)

[jinman]

I was rotary cutter mowing last Monday for most of the afternoon. As I was almost finished, my wife came driving up on our Kawasaki Mule to bring me some cool water. I shut off the tractor and had a drink before attempting to restart, but the infamous PTO lamp was on with the PTO disengaged and I knew exactly what that meant. Since it was fairly late in the day and the tractor was just in a good place, I left it for the night and returned to my house with my wife.

Since we were having a 4th of July party on Wednesday, I just left the tractor sitting until yesterday, when I had time to return with fuses in hand. After two new 10 amp fuses popped on attempting to start the tractor, I knew this was going to be more than the average problem. I had to go somewhere yesterday afternoon, so it was today before I could return.

With my electrical schematic, VOM, and jumpers in hand, I returned this morning, determined to get the tractor going. What I found was that the fuse would not blow if I unplugged the fuel cutoff solenoid. I made a couple of inline ammeter readings and found that the solenoid would sometimes pull more current than at other times. It seemed like it was erratic. I cycled it on and off with a jumper about a dozen times and then replaced the fuse and put the wiring back to normal. The tractor fired right off and after several trys, would not blow the fuse again.

In my opinion, this problem now appears to be associated with the fuel cutoff solenoid. I think I'll increase the size of fuse #2 to 12 or 15 amps and see if that doesn't cure the problem. I just think that the solenoid sometimes drags a little and pulls enough extra current to blow the fuse. That's what my meter reading showed as it sometime indicated around 7 amps and at other times around 10 amps. The rest of the load was only 0.39 amps altogether, so I'm pretty sure the solenoid is the culprit for this problem rather than a "relay race" as I previously thought.

 

[jinman]

I changed fuse #2 to 15 amps last night after the 10 amp fuse blew again. I bought two packs of 15 amp fuses after the 10 amp blew again. I had it working fine for awhile, but it didn't last. The 15 amp fuse seems okay so far. We'll see...I'll report any changes.

 

[LoneCowboy]

You've got a TC40 right?
look at the main wiring harness where it comes over the engine.
My whole wiring harness was replaced, it had rubbed right thru
did exactly that


No matter what, you've got a dead short somewhere, start tracing that wire and somewhere it's rubbed thru.

 

[shaley]

Jim you might want to try a time delay fuse such as a MDL (motor delay). You will still have the protection of the 10 or 12 amp rating but with less nuisance tripping. Sometimes with inductive loads even doubling the rating on a fast blow will still not keep it from tripping. Also, better check what Cowboy says.

 

[Soundguy]

Might be time for a CB.. like for a power window motor.. etc..

My 7610s did that a couple times on a lower amp fuse.. but a 10a has been holding for now.. I think they had a 5A in there originally!!!

Soundguy

 

[jinman]

No matter what, you've got a dead short somewhere, start tracing that wire and somewhere it's rubbed thru.

Brian, it's not a dead short. I read the current with an inline ammeter. It would sometimes go as high as 12 amps and then settle back to 7 to 9 amps. A dead short would either instantly blow a fuse or fry a wire. This is just an erratically high load that can be completetly eliminated by disconnecting the fuel cutoff solenoid. It could be a fault internally to the solenoid, but if it is, it will get worse and I'll soon be blowing my 15 amp fuse. If that happens, the solenoid will get replaced. I also considered putting the solenoid on a separate circuit with a switch to activate it, but I'm not ready to rewire that circuit just yet. I like the protection of not being able to start the tractor if the PTO is engaged or the transmission is not in neutral.

I have a TC45D that's a 2001 model. I think on some tractors, New Holland replaced the fuse with an auto-reset circuit breaker. That or the MDL fuse mentioned by Shaley could be a solution. As Soundguy also noted, the solenoid is an inductive load and can be problematic like a motor load in a power window. Over their lives, these loads can have fluctuating starting current requirements best handled by a CB or a delayed fuse.

 

[Soundguy]

Keep us posted on what you find / eventually have to do to fix it. I realize it may be a good length of time down the road.. etc..

Have you noticed that outside temperature effects it any?

Soundguy

 

[jbman45]

Jinman Hello. We traded a few posts before when I had a bad relay on the lighting system that was a bugger to find but eventually we can track down the problem sometimes even better than the dealer. On your problem I have no suggestions! since if you go back and read all your posts you have done a great job of troubleshooting already. You probably have isolated the fuel solenoid as a root cause correctly and not knowing the cost may want to get one or maybe if available you could replace the coil inside by shopping a bit. Not sure how difficult these are to take apart but if something goes together, ....

Solenoid coils when overheated can draw excess current and also if the plunger is not fully retracting can add a continuing higher electrical load on the coil resulting in a higher draw. You might try externally energizing the solenoid a number of times to see if there's a difference in sound or buzzing indicating the plunger isn't fully retracted. Not sure if it can be cleaned, etc.

Good luck and what a great forum where we get great ideas from each other to get through those crazy headaches...

 

[jinman]

Brian, it's not a dead short. I read the current with an inline ammeter. It would sometimes go as high as 12 amps and then settle back to 7 to 9 amps. A dead short would either instantly blow a fuse or fry a wire. This is just an erratically high load that can be completetly eliminated by disconnecting the fuel cutoff solenoid. It could be a fault internally to the solenoid, but if it is, it will get worse and I'll soon be blowing my 15 amp fuse. If that happens, the solenoid will get replaced.

I hate being wrong.... I hate it even more when I'm right and it costs me money.

The dang solenoid finally shorted out, smoked, and stunk up the place. For the "bargain" price of $81 and change, I now have a new replacement. I'll show the installation soon with photos. In the meantime, I cut the end off the old solenoid to find out if it could be repaired. It can't; it's an interesting but simple solenoid that shorted out internally and finally fried. I'll post some pictures of that by this weekend too.

So...if you are blowing fuse #2 on a Class III Boomer, it may be due to a failing fuel cutoff solenoid. Mine lasted 2000 hours, so I guess I should feel lucky.

 

[Soundguy]

I'll have to keep that in mind when my 7610s gets high hours.. I wonder if they use the same solenoid.

So.. was it an insulator failure? Phenolic washer split?

Soundguy