Early into last night's graveyard shift, my favorite BR350 did something it's never done before. I was toolin' downslope when the throttle suddenly dropped 500RPM (with the associated loss of ground speed)
I throttled down to idle and back up to the governor...no joy...still shy 500RPM...
I rebooted the cat, and full throttle was available again. The mystery of the Checkout Sheet Comment from the Park Groomer who drove my tractor on swing shift was now understood...His cryptic comment: "Engine went to idle while grooming"...
Wait a second..."Rebooted the Cat"?
That's right, modern snowcats are computer controlled, and they load their Operating System every time they start up. As grooming technology entered the 21st Century, groomers learned the Reboot Trick...most glitches can be fixed with the old Restart/Reboot Routine. Most common is the tiller that won't spin...a quick restart will usually restore operator control of the tiller...we reboot to fix everything that isn't damage or breakage.
A half an hour later, again pointed downhill (if only just barely) the same symptoms once more. This time I let it go...I twisted the throttle knob up and down, finally leaving it at idle. The throttle became possessed! Without input from me, it cycled up and down from it's 800RPM idle to 1500RPM...spooky!
I rebooted, and normalcy returned once more.
I keyed the mic and called the Swing Park Groomers. I asked them to give me a shout-out when they finished their shift, so I could park Ol' Faithful and jump in their Bison for the duration. We discussed their cat's pesky glitches, and I told them to finish their List because I could soldier on OK.
An hour later, the Graveyard Wrench punched in and called us on the radio to say he was in the shop.
I replied and told him what was going on with my steed: "It's happened twice, but it hasn't thrown a code yet".
Another hour passes and the glitch hits again...this time it displays a Flash Code. I give the Wrench a call and tell him: "OK, I gotta code, it's 4-2" The Wrench said: "I'll look it up and give you a call back".
The call came 20 minutes later: "It's a non-critical fault. The Throttle Position Sensor is probably failing. It's OK to run it".
I ran it for the rest of the night without any more weirdness.
At the end of my shift, I was fueling up and the Boss walked up to shoot the shit. We marveled at the nearly uninterrupted service my cat has provided this season. It's the oldest cat in the fleet...it will turn over to 8500 hours Saturday...more than half of those hours are my hours...I can say that in 30 years behind the sticks, I've never enjoyed a tractor more than this one.
I'm gonna miss her. Next season we turn her over for a new cat.
I'm optimistic though...I have a long string of great tractors behind me...I'll probably warm to the next victim, too...