2810 blowing fuses

[Anonymous-0]

I have a 1983 2810 that takes spells blowing fuses and won't start. It's an inline 20A. in the hot wire off the solenoid going to the ignition switch. Not sure if it's original. Anyway, I've been up to my elbows repeatedly in the harness and can't see anything wrong. New battery, new cables (hot & ground), new starter and solenoid and new ignition switch. The fuse blows when I turn the key from OFF to the first position before the START position. I've disconnected the lights & the transmission safety switch (temporarily)while troubleshooting without any luck. Could it possibly be the voltage regulator? Not much else is left. AND, it sometimes goes for weeks/months working fine. Then one day... Any ideas? Thanks in advance.

 

[RodinNS]

I don't recall that those things had a fuse in that wire. Mabey a fusible link... Assuming that it has through wiring of at least 10ga feeding the switch I would probably just stick a 30 amp fuse in there and try that. If the tractor has a thermostart unit then that will draw 25 amp... plus you need enough at the same time to pull the solenoid in when you crank... so it's easy to hit that 30 amp mark without any other loads that you might have wired into it...

Rod

 

[RickB]

I also suspect that the 20A fuse is:
Not original.
Not big enough to carry preheat and start control circuit current.

 

[Geo-TH,In]

Steve, Keep in mind a fuse only protects the wire. Don't use the wrong size fuse.

14 g = 15 amp
12 g = 20 amp
10 g = 30 amp

You could cause a fire. When the fuse blows, is the wire hot? I have seen fuses blow because the fuse holder is rusty, doesn't make a good contact with the fuse, fuse gets hot and blows. I've seen fuses blow because the wire's insulation has worn in a spot, shorting to ground. Usually fuses blow because of excessive heat or excessive current.

The only way I've been able to find the intermitant shorts is to install an ammeter in the wire causing the problem and start moving wires around. If that doesn't work, keep an eye on the ammeter and see if it's excessive current, amps, blowing the fuse. LOL

DON'T INSTALL A FUSE THAT IS TOO BIG FOR THE WIRE!
George

 

[Anonymous-0]

Thanks for the help. Actually, I'm a career electrician so I'm very familiar with fuse/wire size. Don't really think this arrangement is original but shouldn't the wire have some protection in it? It goes straight from the hot post on the solenoid through a new inline fuseholder to the common post on the ignition switch. Other than that, the only fuse I can find is built onto (literally) the headlight switch. Old and I can't make out the amperage but it's good. Tractor doesn't have any type of pre-heater, just dashboard and front/rear lights. There is a 120 volt block heater but, of course, that's totally seperate. You know, I may run a #10 wire and try a 30 A. fuse like you suggested, especially since the headlights are fused seperately. I worry about the smaller gauge wires in the harness, though. Could install another fuseholder to protect the rear work light, I guess. This thing is driving me crazy. BTW, my brother-in-law has a 2810 that does the same thing. Go figure!

 

[Geo-TH,In]

Steve, My jublee was converted over to 12 v before I got it and the wiring was a mess. I completely rewired it. Caught a little heck for putting a 30 amp circuit breaker in the 10g wire coming from the alternator out to the +12v . Haven't had the first problem with it. I then made two circuits, one for the ignition/starter and one for the lights. Used 14g wire and 15a fuses.

It wouldn't surprise me, if someone doesn't have a circuit diagram for your tractor.

I just used a pencil and sketched my circuit.
George

 

[RodinNS]

It's definitely not original...
Should the wire have protection? IN my opinion... yes. In reality... a lot of rolling stock doesn't have any protection on the primary supply wires to their terminus. A lot of stuff was generally fused inline after the switches. I guess they figuered that if there was some sort of fuse somewhere in the system it would protect it from overload... which it would. Still doesn't protect it from a short between the fuse and the battery tho...
If I were you I'd swing the battery tray out and have a look for a wire and a piece of synflex feeding fuel to a bulb in the front of the intake manifold... It will be just below/behind where the retainer bolt for the battery swing out is located. That is the thermostart unit. IIRC, that was standard equipment on all Basildon 10 series tractors. To activate you turn the key past the run position until the dash lights go out and hold it there (but not all the way to crank) for 10-20 seconds or until you hear a good pooff from the manifold... then crank. It's got a little heating element in there with a bi-metalic valve that when it gets hot enough will allow some fuel to dribble out on the hot element and make a little fireball in the manifold. This activates manually when you hold the ignition as described AND when the engine is cranking...
I bet if you hung your current clamp on the ignition supply wire you'd find it draws over 30 amp while cranking...

As far as the headlights go... I think those switches were fused on the input side... so headlights, work light and flashers should be fused sufficiently. If not then the outputs are fused separately.

Rod

 

[Anonymous-0]

Rod, I'm not familiar with the thermostart you're describing but I'll sure be looking in a day or two when I have time to work on this thing again. Thanks for pointing it out to me. Are you saying it can short out or add enough load to blow a fuse that is on the edge anyway?

I got 30a fuses and new #10 wire last night but it will be a day or two before I can spend time on it again. Been thinking, too... If I take all the wires off the ignition switch and reconnect them one at a time until the fuse blows, that should tell me which direction to look. Man, I appreciate all the comments. Keep you posted.

 

[Texasmark1]

I have a 1000 series tractors (a few) with the thermostart. One is a push button and the later model which is in the circuit when going from on to start, half way energizes a heater in the thermostart unit. This heater causes a temperature sensitive valve to open and allow diesel to drip onto the hot (glowing hot) wire of the preheater and when it does it catches on fire. The air flow through the intake manifold, once moving the switch over to start, causes these burning blobs of diesel to be sucked into the intake valves of the cylinders and light off the dormant diesel.

I would disconnect the single wire going to the thermostart device and see if your fuse blowing ceases. If so, get a new one.

Mark

 

[Anonymous-0]

Hey guys. I think I've found the problem. Rod & Texas thanks for pointing out the thermostart. No, that's not it but until now I didn't even know it existed. Anyway, I took every wire off the ignition switch except the hot and re-connected them one by one until I got a blown fuse. I then traced that wire to the transmission safety switch. Once I disconnected the switch and jumped the circuit the tractor fires right up and the circuit stays clear. No. I'm NOT going to leave it! Local supply store has one in stock for me to pick up tomorrow. Whenever the High/Low shifter is in neutral (start position) both wires are grounded to the frame making for a dead short. I think it may just be old and the wires have deteriorated over time but I'll have to pull the cap to replace the switch. That's the next step and hopefully the final one. Thanks for the help. If this doesn't do it I'll be back to keep you posted.

 

[Anonymous-0]

Finally! Took the cover plate off the transmission and there it is. One of the wires going to the safety switch was naked and had been shorting out against the underside of the plate. Wire is almost burned in two. I'm going to replace the wiring and the switch since I've got everything torn apart. Thanks for the help. Thought ya'll might want to know.