Excavator won't start. Round 2

[WoodChuckDad]

A few months ago I posted about my excavator not starting. Komatsu PC130-6

http://www.tractorbynet.com/forums/construction-equipment/369723-excavator-wont-start-starter-maybe.html#post4558756

It was the starter. In the process of fixing it, I replaced the batteries, and then replaced the starter.
That fixed it and it has been running great since then.

Until today.....
Yesterday I ran the excavator all day. We were burning logging debris so I kept the excavator going the whole time. Started it up in the morning around 11 am. It turned over sluggishly and cut off. I turned it again and it started up. It was in the 20's F . Ran great all day. No problem. I let it cool down and shut it off at 930 PM.

This morning at 11 I tried to start it up and got nothing. When I turn the key to the on position, the display lights up as expected but when I turn to the start position I get absolutely nothing. No click...no sound of a relay or starter solenoid click. I went back the truck and read my operation and maintenance manual. I went back and tried to preheat the glow plugs before trying to start. (it was 19 degree F). At first I could not turn the key to the heat position. I torqued down on it and got it to move...the glow plug light came on and it indicated that it preheated. I turned the key back to the start position....nothing. I moved the key back and forth to the heat position several times and it loosened up. I never got anything when I turned to the start position. The lights/ relay, etc share a fuse with the start so I don't think that is it. I thought perhaps it could be the ignition switch. That seems like an unlikely thing to go bad but it is possible. I have had to replace starter relays in older cars before but i don't know if there is a starter relay in this machine. I know there is a battery relay but if the battery relay is bad I would expect that none of the lights, etc would work. I spent about 2 hours tonight reading thru a soft copy of the shop manual. That didn't help much.
in the Operators manual I saw reference to a fusible link in the battery compartment....I looked for that but never found anything that looked like what they showed an illustration of.
I'm sure it is possible that the starter I put in has died but that seems unlikely after no more than 30 starts.

Never a dull moment.

Any suggestions?

 

[WoodChuckDad]

I'm following up my own post. Continuing to research the issue and I searched fusible link.
Found this reference to the pc138. That is the model that replaced the 130. I think this sounds like the problem I encountered. Now I need to go back and check the link and then figure out where to get a new one.
Fusible Link - Komatsu PC138USLC Operation & Maintenance Manual [Page 164]

 

[bcp]

I believe I've read several times that there is nothing special at all about a fusible link, except that it is four wire sizes smaller than the rest of the circuit's wire.

Do some research before trusting my memory.

Bruce

 

[KubotaToy]

I cannot help you with the location but on my Link Belt excavator, the starter fusible link tends to blow every winter when there is a cold snap and I have not run it in a while. I believe my links tend to blow because I let the battery's get low from lack of running and it takes more cranking time to start up in cold weather. Like you, I unusually start it once and run it all day, it is always the next day I find it is blown.

If you find it blown, you may be able to get one at a parts store, they had several 12V versions of mine but I needed a 24V, found it at a local tractor dealer as I have no Link Belt dealers around.

 

[bcp]

PS: found some fusible link references.

Catalog

| Repair Guides | Circuit Protection | Fusible Links | AutoZone.com

Bruce

 

[KubotaToy]

PS: found some fusible link references.

Catalog

| Repair Guides | Circuit Protection | Fusible Links | AutoZone.com

Bruce

While fusible links can be in wire versions, his fusible link should look like an overgrown blade fuse. Attached is one similar to the one I use.

 

[EddieWalker]

Do you have a volt meter? When something like this happens to me, I start checking voltage from the key to the starter.

Do you have any safety switches? I've had to bypass every safety switch/button on my lawn mower because they went out one after another.

Does it have a forward/park/reverse lever? When my backhoe wouldn't start, it turned out to be the cable for what direction I want to go. Everything was dead. It worked the day before, but then nothing.

How tight are all your wires in and around your starter? I had a loose wire on some sort of relay on the side of my engine block that the wires from the starter went to. If you hold the wire, or wiggle it, the dozer would start.

Is your starter tight? I replaced a starter once and it worked great, but then the next day it wouldn't start and after awhile, I figured out that the bolts on the starter had come loose.

Did you get the correct batteries? Is it 24 volt and did you replace both batteries at the same time?

 

[WoodChuckDad]

Thanks, guys. BCP that was what I thought the diagram indicated and that is what I looked for. But what I saw was a plastic housing that was similar to the one kubotaToy showed.
Eddie I don't have one here st the farm. I'll grab one tomorrow morning and start checking. I removed the control panel with the starter switch and everything seemed solid. Yes there is a safety switch/ lever to turn off the hydraulic controls and one to lock the swing motor.
Forward and reverse are controlled by Pedal/joystick.
Starter seems tight. I torqued it down good when I put it on.
24V. Both replaced at same time. Correct batteries for my machine. Probably could have kept the old ones but what is done is done. I'm gonna Start chasing that fusible link in the morning.

 

[ktm250rider]

Bad ground?

 

[WoodChuckDad]

Checked wires. I will Probly check again tomorrow.