WE HAVE GOT A300 that when using the hydraulics walking digging or swinging engine will stall checked filters all clean checked servo valves all are good
Check fuel and boost.
we replace the fuel pump about a month but have not the boost planning on working on it tomorrow
Komatsu pc300lc-6 should have the s6d114e-2 which is emissionized 505 cummins... The was a parts and service update for the in-line filter replacement against the fire wall in front of control valve the is a serviceable screen the can be cleaned.. That is the replacement in-line filter...a lot of people do not even know it is there....just sayin.....
I've also seen those filters mounted next to the counterweight. They look like a regular gas filter that you buy at Napa. I've had to pull a couple of dozen out because of that. The auto parts filter is a paper filter. When water hits it the paper swells shut and the fuel can't get through. The original unit has a brass strainer in it. You can blow backwards through it with air pressure and it will clear. There was also a lot of trouble on those machines with the compensator valves. I don't remember exactly what was going on but the local dealer sent out their wrenches with a set in the trucks all the time. It was expensive and wasn't always the problem. Lots of contractors went to other makes after that mess.
Sounds like a torque/ pump control issue, when the engine stalls is it blowing black smoke? if it is there is no shortage of fuel, thus it wont be the filters.