BX engine almost stops on big bounce

[tshep]

2003 BX23, cutting overgrown 'grass' fields.
Maybe 5 places where tractor will bounce over (unseen) ruts.
I'm rolling, trying to get done.

Tractor bogs, but not a load bog. It bogs as though a fuel safety has cut fuel off. Would stop engine until I learned to stop PTO drive, shut down throttle, and wait it out, running rough - maybe 5 seconds - then rev back up and re-engage. And yes, it is enough to throw me up too, I catch on to prevent the subsequent drop.
(If I just raise the seat while running, and put it back down, engine recovers instantly - this is different.)

It seems like those cars where a bump required a fuel reset?

Any parts or processes that inherently act as a safety on a big bounce?

I suppose I could be jostling low lying fuel water 'up' into flow, but only on bounce?
The machine runs fine at all other angles I may work at, up, down, sideways, combos.
Makes me think not.

Any suggestions, as to cause?

 

[RjCorazza]

I would still bet on the seat safety switch. My previous ZD mower would do that when rolling on bumpy terrain, and it was activating the seat switch many times untill I ended up in a fuel starved condition.
The stirring up bad fuel in the tank is also a possibility, as you mentioned. It would be particularly susceptible to that with less fuel in the tank.

 

[BleedingOrange]

It sure sounds like the seat safety switch to me as well. If you want to test the seat switch, pull the plug apart under the seat, and stick a paper clip into the harness side. Try that and see if it cures your problem. Since I am the only driver of my BX2370, I,ve been in test mode since 2016.

 

[dodge man]

I’m not sure reading your post if the engine is stumbling or not? If it is there are two fuel filters on a BX, one up front near the engine and another one towards the back underneath. If you have a mid mount mower on you need to remove it to get at it. It’s almost always the back filter that’s plugged.

 

[bdhsfz6]

Could be a partially clogged fuel filter in combination with the seat safety switch.

 

[Hay Dude]

Seat safety switch or battery cable loose/corroded connection.

 

[tshep]

I will jump out seat switch for test next.

But, the behavior is vastly different...
A seat bobble 'threatens' stoppage, and instantly recovers.

This rut bobble will stop under load, and if I'm quick enough to reduce load, almost stop, and still choke and stumble for 5 seconds or more before recovering.

It sounds like when you're covering from a filter change or other fuel system breach, while getting rid of air and recovering fuel supply.

 

[RjCorazza]

I will jump out seat switch for test next.

But, the behavior is vastly different...
A seat bobble 'threatens' stoppage, and instantly recovers.

This rut bobble will stop under load, and if I'm quick enough to reduce load, almost stop, and still choke and stumble for 5 seconds or more before recovering.

It sounds like when you're covering from a filter change or other fuel system breach, while getting rid of air and recovering fuel supply.

If jumping the seat switch doesn't fix the issue, I would check all wiring (paying particular attention to the fuel shutoff solenoid and electric lift pump). Also check fuel hoses for cracks, leaks, and connections. May not be a bad idea to change out both filters.
FYI, some BX owners choose to relocate the difficult to service filter. I've changed the fuel filter layouts on several types of Kubota machines, but not on a BX. There are several topics here on TBN that address the BX models specifically.