ZD326 Died; Dump Fuel?

[Mr Haney]

I am still working the bugs out of my used Kubota ZD326. I am waiting for parts. I had to hotwire the mower and disconnect the brake switch in order to get it to run. It's a joy to use when I can get it going.

Today while I was mowing, the mower tried to die on me. It did this a few times. I had switched tanks after letting the left tank run dry, so I thought I might have air bubbles in the system that needed to be digested. The problem got worse and worse, so I headed for the house, and the mower fainted in the driveway.

I switched to the left tank before trying to get to the house, and it was after that that the mower decided to take a nap.

The fuel in the left tank is new, and the mower consumed the fuel that was in it before with no issues, so I'm not worried about it. Should I dump the fuel from the right tank?

I am going to change the fuel filters. I don't see any kind of water separator in there anywhere. Have other people installed aftermarket water separators? My dad had a boat with big Racors on it. There ought to be something similar for mowers.

The locations of the fuel filters are not very accessible. Has anyone here tried moving theirs? Seems like an obvious idea, but Kubota put them in such inconvenient places, it makes me wonder if there is a good reason.

 

[Mr Haney]

Another question: what is the purpose of the tank selector? I saw someone on the web say he replaced his with a T fitting. My dad's boat had 4 tanks, and I suppose that if they were all on one fitting, the lowest tank would still have a lot of fuel in it when the highest tank started sucking air, but that doesn't seem to be a problem with two symmetrical tanks on a mower.

 

[JasonW]

I’ll get a picture of the filter I added to my ZD this evening. Do the fuel tanks look clean? Have algae in them?

I also replaced the tank selector with a Tee. I still need to add check valves to them. If I park it overnight on an incline the fuel level will equalize and the lower tank will have more fuel in it.

 

[Mr Haney]

Thanks for the help.

I couldn't get much of anything out of the right tank. I bought a siphon the other day, and the tubing will not straighten, so I can't get it past the curve and down into the bottom of the tank.

The gauge is clearly off. It reads nearly full, but the right tank contains much less fuel than the left. I hope I didn't just run it dry. But it was slowing down sporadically, so it looks like the filters are bad. Sadly, I have to drive across town to get them.

The fuel in the left tank looks perfect, but I can't siphon off the bottom to be sure.

 

[JasonW]

Have you downloaded a service manual for your model? Or at least the owners manual?
They are useful in many ways even just the diagrams. Also Messicks has good diagrams to show parts layouts.

If you can see fuel in the tank I doubt you ran it dry. I ran mine almost out of fuel when I added this filter/water separator mainly for it to catch some water that was in the tank and it ran for a while after I couldn’t see any fuel in the tanks. It started missing and was low on power first, I immediately idled it down and drove it to my shop to fill it up.

This is what I added right after I bought it a few years ago. It’s a fuel filter from a L3800 and possibly other models, I think it was around $30 from the dealer. I did have to plug the top vent in it with epoxy.

The fuel goes from the tanks to the added filter, the first original filter, fuel pump, and second original filter, then to the injection pump. When I added it I did replace the original filters before and after the fuel pump. They are difficult to access but if I remember I removed the battery tray and the original filters and fuel pump are attached to a bracket that comes together.

 

[Mr Haney]

I don't know if I'm the dumbest person on the forum or what, but I just put a couple of gallons of diesel in each tank, and the mower ran. I think I ran the right tank dry at the end of my session. It looks like Kubota's approach to fuel measurement caught me flatfooted.

The only fuel gauge is for the left tank, so naturally, it says "RH TANK" on the control panel. You're supposed to run the mower on the right tank. Then an idiot light by the "RH TANK" text turns on, and you're supposed to switch to the left tank. Once you're on the left tank, the gauge tells you how much fuel you have left. So left tank: gauge; right tank: idiot light.

My best guess is that I had bubbles in my fuel lines that made the mower slow down on the left tank, and then I switched and ran the right tank dry, thinking the gauge said it had fuel in it.

When you look in the empty tank, it looks like there is fuel in it, because fuel stands in a cavity by the cap opening.

Thanks for suggesting manuals. I have the owner's and workshop manual, and I have been reading a lot, but I just assumed I knew how to read a fuel gauge, so I didn't study that. A man's got to know his limitations.

I will check out that filter you added. Looks pretty neat. I just don't like the idea of opaque filters with no way to see or discard water and slime.

I'm going to run on the left tank and see if the gauge does anything.

 

[GreensvilleJay]

I'd drain BOTH tanks, properly clean and inspect them. yes, probably a PITA but if there's ANY 'stuff' inside,better to get it out NOW and KNOW you've got CLEAN tanks.
I had 'something' in the tank of my BX23s 6 years ago, took 3 days to get tank out, clean it, then FINALLY found a small, black sliver of plastic in the exit spigot ! There is NO way any camera or light would have seen that, and just backblowing would only have made it float around and cause future problems. I've also added a 'cold coffee mason jar filter' to keep 'stuff' from getting in. So far 6 years, 1000+hrs and ZERO fuel tank issues.....
In the end it's your machine, your time, do what you want......

 

[Mr Haney]

I wonder if I can get an endoscope down in there.

I just switched to the left tank, fired the machine up, mowed a little, and ran it around the yard. The mower slowed down a little right after I started it and then ran perfectly.

 

[mikester]

When I run on tank dry it will bog down as you described. My ZD326 only came with cheap inline fuel filters. You could eliminate the tank selector valve, my preference is to keep it and use it as a reserve. I've often toyed with adding a second fuel gauge to replace the next to useless low fuel indicator light (light's on, I have another hour or two of mowing left?).

 

[GreensvilleJay]

so recap....
it runs fine on the LEFT tank and lousy on the RIGHT tank ?????

I looked at parts finder,
so if true, then you have 'junk' in the RIGHT tank. remove, inspect,clean, confirm, reinstall.

if it still runs lousy on the right, problem must be the selector valve.

 

[Mr Haney]

I still have to mow the rest of my yard, so I will be trying to do that today. My best guess, based on my failure to comprehend the gauge system, is that I will not have any problems.

I suppose I will learn a lot when I replace the filters. Kubota decided to make them opaque, but I will crack them open to see what's in them.

 

[whitetiger]

A simple way to change the filters is to remove the battery cover, unplug the electric lift pump's wire connector, remove the hose from the tank to the first filter, remove the hose from the outlet of the second filter, remove the two bolts beneith the battery box. The bracket, pump and filters falls onto the floor. Put the bracket in your vice, R&R filters, reinstall.

 

[CGMKCM]

Get a bottle of this and treat both tanks and top off the fuel. P.S. get on the ground and visually inspect both fuel filters. I would bet they both need to be replaced.

Try swapping fuel tank caps from side to side and see if the problem moves to the other tank. I have found that the fuel tank caps can have venting problems. I replaced both caps over the last few years. Kubota has redesigned the caps several times since 2010. The parts guy said the part number has changed 7 times. I also replaced the cap (same P/N) on my RTV 1100-C. I was having fuel starvation problems and the fuel treatment and new cap fixed the problem.

I re-fuel after mowing and shift tanks after I re-fuel. I keep all my fuel tanks topped off.

 

[Mr Haney]

I will pick up that additive. I was going to get some Biobor, but the fuel looks good. I guess I can't tell much unless I can see the bottom of the tank, though. I suppose I should buy it.

There used to be an incredible biocide called Enhance, and it was 10 times as good as Biobor. They quit making it. Maybe it causes some disease or other.