Will not start

[onekpa2]

It's a Thomas 85 actually,{first mistake) with a Kubota D722. I've had this problem for years and now cant get it to turn over. I used to be able to jump start with a booster or from my truck but that doesn't even work any more. I turn the key and it just clicks. This all started when I had a friend / mechanic work on it. We added a key pad after someone attempted to steal it. So far I have replaced the Ignition switch, the battery, the alternator, pulled the starter and tested it, chased the wiring all over. Everything checks out but it just wont turn. On the rare occasion in the past when I could get it running all the electrical will shut off, but the engine keeps running. Very frustrated! If anyone has tried to work on one of these, you know how tight access to anything is. All help is appreciated.

 

[TriHonu]

For starters, you posted in the Bobcat Forum so you may not get a lot of responses.
Since you are stating you have checked the electrical, it is time to check if it is an mechanical (engine or hydraulic) issue.
However, here goes:
1. Are the Auxiliary Hydraulics in neutral? This is the center pedal on the floor or if yours has the electric solenoid valve, make sure the switch in the cab is off. If it is engaged you are pressurizing the circuit as the engine starts to turn. The starter can not overcome that load. If the pedal is in neutral, you could check if the valve is stuck by looping a hydraulic hose from one auxiliary port to the other to allow the fluid back to the tank. You could also disconnect the engine from the hydraulic pump and then try to start it.
2. Does the engine turn at all? Can you bar it over by hand?
3. Have you tried jumping directly to the starter and manually powering the starter solenoid?
Here is a copy of the Thomas 85 Service Manual.

 

[bobcatguy]

Have you jumpered the starter? If you hear a "click" it would tell me you're not getting enough battery voltage to the starter to turn it.

 

[antfarmer2]

Have you jumpered the starter? If you hear a "click" it would tell me you're not getting enough battery voltage to the starter to turn it.

Make sure your batt cables are good and connections are clean

 

[onekpa2]

Make sure your batt cables are good and connections are clean

Thanks Guys, I took the starter out and bench tested it, every thing worked out. This model has a boost lug so I have disassembled all connections and wire brushed every thing. I did notice the wire from the starter relay to the solenoid had a splice. The original wire appears to be a 10 ga and the splice is like a 16 ga, will this cause a voltage drop? When I turn the key, the solenoid clicks in but the starter doesn't turn over. In times gone by, I would be able to jump start but would have to cycle the key dozens of times before it would turn over. I have tested the ignition switch and it seems to be good. Also, as mentioned before, when I could get it running, I would loose all electrical and have to shut off the engine manually. Thanks to all.

 

[antfarmer2]

Thanks Guys, I took the starter out and bench tested it, every thing worked out. This model has a boost lug so I have disassembled all connections and wire brushed every thing. I did notice the wire from the starter relay to the solenoid had a splice. The original wire appears to be a 10 ga and the splice is like a 16 ga, will this cause a voltage drop? When I turn the key, the solenoid clicks in but the starter doesn't turn over. In times gone by, I would be able to jump start but would have to cycle the key dozens of times before it would turn over. I have tested the ignition switch and it seems to be good. Also, as mentioned before, when I could get it running, I would loose all electrical and have to shut off the engine manually. Thanks to all.

Bad connection I would start with your splice and run a full and proper wire

 

[Tazza]

Bad connection I would start with your splice and run a full and proper wire

I'd use a jumper at the starter to see if it engages and cranks, if it does, the issue is between the starter and key. So then work back, starter relay then key switch.
Not sure the wire gauge would be an issue, the power to the relay just turns it on and off, but the splice could be the issue too.

 

[onekpa2]

I'd use a jumper at the starter to see if it engages and cranks, if it does, the issue is between the starter and key. So then work back, starter relay then key switch.
Not sure the wire gauge would be an issue, the power to the relay just turns it on and off, but the splice could be the issue too.

So with a little spare time, I ran jumpers from the starter post and the solenoid post to a push button switch. I push the button a few times and it cranks, but have to repeatedly cycle the switch to get it to catch on occasion. Like I said before, I bench tested the starter the same way and it turned over every time. Is there some other ground than just the starter bolted to the engine mount? There is a ground wire from the starter mounting bolt to the frame and all connections look good there.

 

[antfarmer2]

So with a little spare time, I ran jumpers from the starter post and the solenoid post to a push button switch. I push the button a few times and it cranks, but have to repeatedly cycle the switch to get it to catch on occasion. Like I said before, I bench tested the starter the same way and it turned over every time. Is there some other ground than just the starter bolted to the engine mount? There is a ground wire from the starter mounting bolt to the frame and all connections look good there.

Follow the neg off the battery