Kubota M7040 blows off a fuel hose --

--repeatedly. The hose comes off the rear of the pump and connects to a small, plastic canister.

Tractor has 290 hours; serial # M7040D 83068.

Did the same last winter and I had the dealer make a service call. He reconnected the hose and changed the fuel filter. Didn't know why it blew. The water separator's red disk was (and still is) at the bottom of the cup. Fuel is treated with Power Service.

The engine continues to run at all rpm's after the hose blows off but will not start after it's turned off.

Temperatures have been daytime teens and 10F or so at night for the past week, but the tractor wasn't started until yesterday afternoon after a day of high 30's.

Any idea what causes the hose to blow?

Any harm done if I reconnect it? Another $300-plus service call seems like a waste for a temporary fix and not even a guess as to the cause.

What's the function of the little green/white plastic canister that the hose is connected to? There are a few of them in the same vicinity.

Thanks for any help.

I'm guessing its part of the auto air bleed setup most larger Kubota's have.

are you running a 50/50 mix of #1 and #2 diesel? The last time I checked power service will not lower the cloud point of diesel. probably partially jelling up in the green and white thing and blowing the hose.

those are check valves make sure line is not kinked. I just checked to see if there is any bulletins on that machine for fuel system and there is none. my money is on a blockage of some sort. those check valve's are on the return side .

Well you have got another opinion. 8v92 is a dealer and is right on about the plastic thing being a check valve in the return line system. Hard to explain without you having access to a parts drawing but we have had one or two instances of the tank vent being plug buy wasp. Will be a loop of line in or on front firewall right at back of hood. hard to see but it comes up and goes back down. Take a light wire like electric fence wire and work down the hose a little way. Will not hurt to replace the hose on the valve and you might add a better clamp like a radiator hose uses.

"mooger " interesting handle, where does it come from? Bill

I agree with 8v92, there is a blockage and, since the engine will stay running it is obviously a return line. I would remove both ends of the line and blow thru them (not thru the check valve however). If no blockages are found I'd replace the check valve. It could stick or have ice in it causing the blockage. I think the check valve keeps the fuel system primed for starting. You don't need a filter because the filters look to me to be on the suction side. Mark

Thank you all!

hd6gtom -- Don't know if fuel is #1 or #2 but I'll find out. I got rid of the tanks a few years ago and fill 5-gallon cans from the local Phillips 66 station. The fuel was bought recently, and the station is a busy place. I'll also check into any additives that might prevent gelling.

3v92guy and Mark Robke -- I'll check for kinks in the hoses, and it's good to know there aren't any service bulletins on the issue. There's a consensus on blockage as the most likely cause, so I'll disconnect all the small hoses and check. The check valves are easy to get at so I'll just replace them.

jm. -- I noted down the route of the vent line and will use a wire as you described, and buy a hose with the check valves. I'll replace the spring clamps with SS hose clamps, but only one or two at a time.

I always bought parts catalogs and service manuals for the old tractors, and could almost always muddle through. I didn't get them for this tractor because I don't have a chance at trouble-shooting it.

Thank you, Ken.

Bill, 'mooger' is just a silly, made-up word, an inside joke with an old friend, and not quite clean enough to define in mixed company. I started reading and posting occasionally at the Ford forum in 1999 using a different handle. Years passed and a post was refused one day - registration was required but I'd missed any notice of it, and somebody had copped my old handle.

if you pressurize the fuel tank ( I just hold my hand over the fill hole and blow air in the tank ) you should here air coming out the vent hose it will be cable tied behind the hood hinge support?on the left hand side of tractor.

(quoted from post at 02:56:02 12/27/13) if you pressurize the fuel tank ( I just hold my hand over the fill hole and blow air in the tank ) you should here air coming out the vent hose it will be cable tied behind the hood hinge support?on the left hand side of tractor.

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Thanks, ih_bug, that's easy enough to do so I'll reel out the air hose.

My M7040 got a fuel leak in fuel return line last Winter in sub freezing temps. The check valve you mentioned came loose. I suspected icing of fuel. I added fuel anti-gell,drained water separater and installed a better hose clamp.

After reading this post last month my 7040 did the same thing at work. I sent discussion link to my dealer and this is the reply. Mine is under warranty so its getting replaced.

I called kubota again and spoke to another tech. He stated that is a known problem with that check valve. They made the assumption that it is moisture inside that check valve and it freezes, the same thing that I assumed. They have made a rolling vendor change (who ever makes that for kubota got dumped) to a different check valve. The new one is supposed to be trouble free

(quoted from post at 11:03:10 01/22/14) After reading this post last month my 7040 did the same thing at work. I sent discussion link to my dealer and this is the reply. Mine is under warranty so its getting replaced.

I called kubota again and spoke to another tech. He stated that is a known problem with that check valve. They made the assumption that it is moisture inside that check valve and it freezes, the same thing that I assumed. They have made a rolling vendor change (who ever makes that for kubota got dumped) to a different check valve. The new one is supposed to be trouble free

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I personally see no need for the check valve in the return line and the next time my check valve blows off it will be removed for GOOD.

Ok I know this post is old (2013) but this just recently happened to me. Bushogging with the Kubota and smelled diesel.put her in the barn to figure out why.saw diesel dripping.and then after investigation found the check valve was not connected to the bottom line. Just like this case.

To confirm next steps (I am both new to kubotas and to diesels not to mention a wee bit slow on the uptake), I need to replace the check valve and then follow the air bleed procedures? Tractor never shut off despite the leaking diesel but I have reconnected the fuel check valve and the tractor will not fire or crank. It s a 2017 with about 700 hours and in great shop and ran perfectly before this little snafu.

Thanks

No air bleeding required because that check valve is located on fuel return to tank line. Just replace check valve with new hose clamps. I used adjustable hose clamps on my M7040

So do you have any thoughts as to why the tractor now refuses to fire or crank? This is the only thing that s happened

(quoted from post at 09:37:20 09/01/23) So do you have any thoughts as to why the tractor now refuses to fire or crank? This is the only thing that s happened

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Did you purge all the air from the fuel system. There's a priming pump on top of the fuel filter housing.

(quoted from post at 00:57:05 09/02/23)

(quoted from post at 09:37:20 09/01/23) So do you have any thoughts as to why the tractor now refuses to fire or crank? This is the only thing that s happened

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Did you purge all the air from the fuel system. There's a priming pump on top of the fuel filter housing.

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I haven t but I was thinking that could be the problem. However some are saying because it s a return fuel line there cannot be air and some say there will be. And I haven t read where it s a step when replacing the check valve. I think I will do that to see if it makes a difference. Would a bad check valve prevent the tractor from cranking after turned off? The tractor was running fine even with the valve disconnected and diesel coming out but upon reconnect it won t fire up at all

I've owned a Kubota M7040 since 2012. I've turned fuel control valve off as a thief deterrent when parking tractor away from my place. I've then started engine with fuel valve in off position & engine died from lack of fuel. Turn fuel shut off valve to on position. Engage starter & engine would start operating in short amount of time with no fuel line bleeding required.

I would loosen line at check valve & attempt to start. On other type fuel system a plugged return line can keep engine from operating or fuel control solenoid could have failed.

I haven t but I was thinking that could be the problem. However some are saying because it s a return fuel line there cannot be air and some say there will be. And I haven t read where it s a step when replacing the check valve. I think I will do that to see if it makes a difference. Would a bad check valve prevent the tractor from cranking after turned off? The tractor was running fine even with the valve disconnected and diesel coming out but upon reconnect it won t fire up at all

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I have a 9540. The fuel lines you are having problems with are some of the worst I've ever seen. My tractor has a little over 400 hours on it, is parked out of the sun, and they've ruptured several times. Kubota fuel line is outrageously expensive and that check valve you're talking about is $60 if I remember correctly. I learned the hard way a couple of weeks ago that the NAPA fuel line I substituted is not rated for diesel, as it broke down and blew off the same check valve. The engine will run all day blowing diesel out the fuel line at the rate of several gallons an hour, but shut down, reconnect (or replace) and she requires a prime to start. There's no fuel line blockage, the fuel filter and screen are fine. If there's a restriction, it may be in one of those check valves, but I can't see inside and I don't feel like spending $60 for $0.60 plastic parts. I had a biology problem that I eliminated with biocide and a few filters. Most of the dead biology ended up in the screen, but it took out the filter body and priming pump. The priming pump is not rebuildable like the screen. The replacement works for many applications and the first thing I noticed is the offending return line is optional. One of these days I'll get mad enough to think through Kubota's fuel line engineering and figure out if there's a better way to plumb the fuel return because that tangled mess of rubber lines is the worst thing about my 9540 after the fact that it only has half the ability of a MF or Ford tractor of equivalent hp. My advice is: repair the fuel line and purge the fuel system. If she starts, expect more trouble in the same place and keep going until the fuel line blows off again.