ZD 1211- Wanting fuel tank to equalize

[workinonit]

I'm a bit confused abiout these fuel tanks as well. I didn't realize they had check valves. I know mine has a bypass line in the top of the tanks to equalize the preassure. I could have sworn when I first brought mine home the dealer fille the left tank, the right was almost empty and after trailering home and running for a while the gauge showed 1/2 tank. So I assumed the tanks equalized but apparently that wasn't the case. My concern is if this particular unit tends to run fuel out of the left tank first I could run out of fuel with a full right tank. I thought about closing thge right hand tank valve and running the left first before valving the right back in. It's kinda cheesy that they didn't put gauges on both tanks.

 

[Brown Dog]

… the check valves being there is to prevent fuel from leaving one tank overfilling the other when mowing on slopes."

I keep mine stock for just that reason ….

Mine is still stock as I mow a LOT of horizontal swipes on Steep Banks in both directions.

I’ve noticed sometimes one of my tanks holds more at fill ups than the other side & in no particular pattern

 

[Brown Dog]

Anybody else have input on tanks drawing equally ?

 

[RjCorazza]

I removed the individual tank filters and installed the OEM filter after the "T" fitting. My tanks were occasionally drawing unequally due to one filter having a higher resistance. I also added large 2u Racor filter and an extra lift pump to get adequate flow.
So far it's been working fine, but I suspect my service interval will be shorter with the fuel from both tanks going through the one OEM filter. 120h so far using the old smaller type, so I'm not worried about it.

 

[Brown Dog]

RjC
Do you still have the OEM check valves in place ?

 

[RjCorazza]

RjC
Do you still have the OEM check valves in place ?

Yes, I left the check valves in place.
I agonized over several plumbing possibilities... There are lots of ways to skin the cat.

 

[BobinCols]

My ZD1211 drew pretty equally the first three years since new. Then the right hand tank (as sitting on machine that has the fuel gauge) always stayed full. I could turn the left hand tank fuel valve off and it would run fine off the RH tank and fuel and gauge would go down. Blew air in fuel cap vents etc..
Finally two weeks ago I purchased two new filters from Kubota and removed the checkvalves. Sadly the check valves are 5/16" on inlet end and 3/8" on outlet end. So that means the "T" has two 3/8" inlet ends and the outlet is 5/16" that goes to the motor. Trip to parts store to get a "T" that was 5/16" on all three sides and a short piece of 5/16" fuel hose to fill in the areas where the check valves were taken out. Now draws from both tanks again. Hope this helps.

 

[RjCorazza]

I removed the individual tank filters and installed the OEM filter after the "T" fitting. My tanks were occasionally drawing unequally due to one filter having a higher resistance. I also added large 2u Racor filter and an extra lift pump to get adequate flow.
So far it's been working fine, but I suspect my service interval will be shorter with the fuel from both tanks going through the one OEM filter. 120h so far using the old smaller type, so I'm not worried about it.

I updated this in another thread, but FYI my uneven fuel draw returned and I converted the fuel system back to stock.
It seemed to draw equally for a while, but after maybe 30 hours (?) it mostly draws from the left tank. I can live with it but it bothers me. Curiously, the left filter is always 1/2-3/4's empty of fuel, while the right filter is always full. When it was drawing equally both filters remained full.
As far as the check valves, I mow on a lot on inclines and don't want the fuel moving from the high side tank to the low side so I'll leave them on.
I'm starting to think this whole problem is caused by slight manufacturing tolerances in the filters themselves. I plan to switch the current left and right filters around and see what happens.