Komatsu mini excavator won't start

You just go to the link I attached I'm sure you will get the solution of your problem -

https://www.reliable-store.com/products/caterpillar-cat-301-5-301-6-and-301-8-mini-hydraulic-excavators-full-complete-workshop-service-manual-pdf

Normally with any of the mini excavators there under the seat or stored on the right side under the hydraulic tank cover, but as our company refuses to buy any of the JBC garbage thats only a guess at to where that podunk company puts there batterys all our mini's are Kubota up to the 080, anything bigger will be John Deere, Case or Komatsu.

Could be a bad starter motor the brushes get worn out inside the starter motor try tapping on the starter with a hammer not to hard if it starts after you tap on the starter toward the back were the brushes are then you have a bad starter or you could have a bad starter solonoid hope this helps

Problem Engine abnormal noise

On this website you find fuse box diagram and description for Komatsu PC Seires

http://www.autogenius.info/category/komatsu/pc

If the engine cranks but won't start, the battery and starter are out of the picture.
When it won't start, someone will need to check fuel pressure and for spark at the plugs to proceed.

Do you mean it won't start, or won't crank.
You should have a neutral safety switch between the key switch and the starter to prevent you from cranking the engine in drive or reverse.
A defective switch would keep the engine from cranking.
A mechanic would check for voltage at the starter on the wire from the key switch and go from there.

Try reconnecting the tracks togeather it may not be easy but my Komatsu toy model excavator has the same problem one of the tracks got jammed while i was playing with it so I'm trying to put them back togeather i also have the PC 450 LC model.. I managed to reconnect some of the tracks togeather but its not easy and be careful not to loose and parts

change the starter motor.