I have a komatsu PC 400-7l that once it gets cold (30*f or less) just dies unexpectedly. It's done this the last two winters, and I have done the following, changed fuel filters multiple times, checked fuel tank valve, used number 1 fuel, replaced hand fuel primer, and inline fuel screen. It does restart with some cranking and does run longer before acting up the more fuel that is in the tank. I am going to start replacing rubber hoses and drain tank of fuel to eliminate foreign material and air leaks. If anyone knows of any other screen, filter, or problem area I could use some pointers. The machine has 8000 hrs and doesn't do it in the summer time and fuel source is clean and fresh with multiple other machines running off same fuel supply. Any help would be appreciated .
Sounds like you have fuel stop solenoid that is getting weak .what engine do you have in the 400-7.
It has the eleven liter motor
How low was the tank when you first put the No. 1 in, and how much since? We had a 9030B that acted identical. After getting bit two winters in a row, we would get it as low as possible, almost running empty, then top with 1 a day or two before we knew it was going to get cold. Change filters at the same time, never bothered after that. I have no idea why it was so fussy, just learned how to deal with it. You might need to get it into a heated shop, pump tank empty, and start over. Good luck. This new ultra low fuel sucks.