GBJeffOH
Active member
Equipment
L4060, EA Grapple, 6' LP Brush Hog, 8' snow plow, 6' LP tiller, EA Forks, Spraye
What is number 80 and where is it?
- Thread starter GBJeffOH
- Start date
Hopefully, this will address the fuel gauge question and yours. Some of this is speculation, since the parts diagrams are not perfectly clear. You can double check on your tractor.
Parts 50, 70, 80 make up a check valve. 80 is a flapper and 70 is the seat. It allows flow from the right tank to the left.
The filler neck is on the right tank, and the level sensor is on the left. The fuel pump, I think, draws from the left tank. There are return flows from the fuel pump(s) and maybe the injectors, and I think these also return to the left tank. So, everything in the system is transferring to the left tank. The vents and 'reserve tank' route the left tank overflow to the right.
After a while the left tank is full and the right may be empty. Then, as the left draws down, the gauge reads the falling level in the left tank - the right is already empty.
So, using the fuel gauge, you can't know how much is in the right tank. Maybe use a dipstick. If the gauge is reading full, you know you have at least 1/2 of total capacity (assuming tanks are equal size).
It can confuse refueling also. Say you've run 'til the left tank is showing 2/3 full. Park on level ground and shut the engine off. Now you can add 1/2 tank of fuel (in the right tank) and the gauge won't move because the level in the right is lower than the left, so the two won't equalize. Once you've added enough to equalize the tanks, the gauge will read both.
Parts 50, 70, 80 make up a check valve. 80 is a flapper and 70 is the seat. It allows flow from the right tank to the left.
The filler neck is on the right tank, and the level sensor is on the left. The fuel pump, I think, draws from the left tank. There are return flows from the fuel pump(s) and maybe the injectors, and I think these also return to the left tank. So, everything in the system is transferring to the left tank. The vents and 'reserve tank' route the left tank overflow to the right.
After a while the left tank is full and the right may be empty. Then, as the left draws down, the gauge reads the falling level in the left tank - the right is already empty.
So, using the fuel gauge, you can't know how much is in the right tank. Maybe use a dipstick. If the gauge is reading full, you know you have at least 1/2 of total capacity (assuming tanks are equal size).
It can confuse refueling also. Say you've run 'til the left tank is showing 2/3 full. Park on level ground and shut the engine off. Now you can add 1/2 tank of fuel (in the right tank) and the gauge won't move because the level in the right is lower than the left, so the two won't equalize. Once you've added enough to equalize the tanks, the gauge will read both.
GBJeffOH
Active member
Equipment
L4060, EA Grapple, 6' LP Brush Hog, 8' snow plow, 6' LP tiller, EA Forks, Spraye
I was going to suggest you could drill a hole in the check valve just big enough to equalize the tanks, but that's not a good idea. I think Kubota is doing everything possible to prevent running the fuel pumps dry, which the common rail systems really don't like.
they've used check valves on lawn mowers in the past too. Kinda dumb, but when they work they do the job.
On the mowers (not familiar with the tractors.....) the check valves disallow fuel siphoning from one tank to the other, say if you are mowing a hillside and the high side tank goes empty, normally that would result in a dead engine. Also, the high side tank will fill the low side tank in no time if parked or operated on a long hilside. The check valves keep that from happening.
Probably same deal with the tractors.
Reminds me someone called me a while back, had a M6800 that would drain one tank but not the other. I didn't look at it, but i wondered if the M6800 cab has the check valve assembly in the crossover line as well?
On the mowers (not familiar with the tractors.....) the check valves disallow fuel siphoning from one tank to the other, say if you are mowing a hillside and the high side tank goes empty, normally that would result in a dead engine. Also, the high side tank will fill the low side tank in no time if parked or operated on a long hilside. The check valves keep that from happening.
Probably same deal with the tractors.
Reminds me someone called me a while back, had a M6800 that would drain one tank but not the other. I didn't look at it, but i wondered if the M6800 cab has the check valve assembly in the crossover line as well?