My 6415 (7000 hrs) has developed erratic rpms intermittently. When it happens, the glow plug light flashes and the hand throttle becomes inoperable. I think the foot throttle still works, but cant confirm. The tractor runs great otherwise. Any help would be appreciated. Thanks. A.P.
The glow plug light is also a warning light that basically tells you there is an error code active. Lots of things could cause the problem including water in the fuel filter. Look in the glass bowl on the bottom of the primary filter to see if there is any water visible. Also the connection on the injection pump solenoid could be loose or corroded. I would look at those 2 things and if that isn't the problem, You would be best to get someone to plug into it and pull the codes. Could be injection pump, throttle sensor, wiring, computer, etc. If you find out what code you have, I can help track down the problem.
We have a 6215 that starting doing this right after we bought it (I suspect it's the reason it was traded in), the dealer replaced (had rebuilt by an independent company) the injection pump (Stanadyne DE-10) 3 times. Finally they found a short in a small section of the wiring harness. They spliced/replaced the bad part of the harness and it's been running perfect since.