Diesel Kubota no fuel issue

Spikeit

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Yesterday I picked up a Snapper Z mower with the Kubota D722 engine. From the injector pump, with the fuel lines removed, only one port discharges fuel. The other two do nothing. I removed the pump and all three "fingers" (they look like rollers lifters) move up/down, everything looks clean and the fuel cutoff is ON. Could it have a bad lift pump? For 50 yrs I've been a gas mechanic and unfortunately doesn't know a lot about diesels. Any ideas/suggestions would be greatly appreciated.
 

bertsmobile1

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Deisels are not mu strong suit either however there are two types.
Timed pumps
and
Timed injectors

Timed pumps.
There is a rotary valve inside the pump so it only pumps one line at a time, at the correct time to overpressureise the injector to inject fuel.
or a high pressure piston for each line and a cam to work the high pressure piston.
These will have a single fuel line going to each injector and may or may not have a drain line from each injector with might be a daisy chain with banjo fittings.
Most old diesels work this way

Timed injectors
The pump simply pressurises a common line that goes to all the injectors then a check valve before returning to the tank.
These will have a wire on top of each injector to control the firing sequence, most modern injected cars work this way as it is a lower pressure system and uses a solenoid in the injector to force the fuel into the cylinder.
 

Spikeit

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Yesterday I picked up a Snapper Z mower with the Kubota D722 engine. From the injector pump, with the fuel lines removed, only one port discharges fuel. The other two do nothing. I removed the pump and all three "fingers" (they look like rollers lifters) move up/down, everything looks clean and the fuel cutoff is ON. Could it have a bad lift pump? For 50 yrs I've been a gas mechanic and unfortunately doesn't know a lot about diesels. Any ideas/suggestions would be greatly appreciated.

Additionally, the guy I bought it from had taken the injector pump off. I don't know if the motor was turned over while it was off but if it was, does this get the pump out of time? He had taken if off for the aforementioned (above) reason, no fuel through the pump so I've basically checked the same things he did. What I haven't checked yet is it getting fuel TO the pump. This motor has the small injector pump that fits into a cavity in the block and runs off the cam.
 

cpurvis

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Injection pumps are not something you want to shade-tree.

If you think the pump is bad, take it to an injection pump shop and have it checked out. Odds are they will tell you it's OK because they rarely go bad.

Next you have to find out how to put it back on and time it. You'll need the Kubota service manual for that or someone on here who can step you through it.

My guess is probably what happened was someone ran it out of fuel and all it needed was to be bled.
 

Spikeit

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Injection pumps are not something you want to shade-tree.

If you think the pump is bad, take it to an injection pump shop and have it checked out. Odds are they will tell you it's OK because they rarely go bad.

Next you have to find out how to put it back on and time it. You'll need the Kubota service manual for that or someone on here who can step you through it.

My guess is probably what happened was someone ran it out of fuel and all it needed was to be bled.

Don't take this personally because I didn't. I know you didn't say I shade tree. You were just making a statement but I don't shade tree. I do it once, do it right, because I don't like covering the same ground twice. :) As for suspecting the injector pump, at this point I don't suspect any one thing which is why I'm here asking you experts for some pointers. I'm not a lost goose mechanically and pulled wrenches for many years but am somewhat lost when it comes to diesels, especially troubleshooting. I understand the principal, have changed injectors, glo plugs and bled systems of air, just general things but never have gotten into troubleshooting so here I am. For starters the bowl/filter/attaching nut on the fuel/water separator are missing so someone bypassed it putting the fuel line straight to the lift pump. Not causing my fuel problem I know but that IS "shade tree." I thought of it having been run dry of fuel but having a lift pump wouldn't cause no fuel at the inj pump, lift pump side, unless that pump is bad. Tomorrow I'll pull the injectors so it'll free spin and start with the lift pump and see if it's putting out. I absolutely need what you said, a shop manual to time the pump but haven't found one online. This mower, besides being pretty nice with only 527 hrs, assuming the meter works, has a 73" cut so it's a hoss and I want to put it to use!
 

bertsmobile1

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Usually a timed pump will run off the cam shaft and be keyed so it goes back in the right place.
Some have a stepped drive so they can be 180 deg out.
Some photos would be a big help.
There will also be a lift pump hiding somewhere, usually electric
JD have a bad habit of hiding them inside the fuel tanks or under the rear fenders.
The lift pumps usually also have a fuel filter ( to protect the pump) and these get clogged with debris in the tank. thus no longer supply fuel to the pump.
And I am not 100% sure you have a timed pump in any case, again photos would be good.

Don't know about what you get in the good old USA but down here diesel is only guaranteed for 60 days ex refinery and the new brews goes off really quickly and just like the new "petrol" leaves a stick residue that will not redissolve back into the diesel so has to be mechanically cleaned off.
Diesel pumps are a specialist job and most do more damage trying to fix one .
Lots of very close fitting very finely finished parts that can literally be damaged by holding them in a bare hand.
Some lift pumps supply fuel at pressure against a check valve, some don't.
I have a few of 40's , 50's & 60's tractors to play with.
Stuff that is mechanical I can handle but the new electronic stuff leaves me cold.
 

halflife trackball

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Yesterday I picked up a Snapper Z mower with the Kubota D722 engine. From the injector pump, with the fuel lines removed, only one port discharges fuel. The other two do nothing. I removed the pump and all three "fingers" (they look like rollers lifters) move up/down, everything looks clean and the fuel cutoff is ON. Could it have a bad lift pump? For 50 yrs I've been a gas mechanic and unfortunately doesn't know a lot about diesels. Any ideas/suggestions would be greatly appreciated.

k. hmm only mechaniccs know
 

EngineMan

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You maybe able to work it out by this...!

bleed the fuel system. turn the key to AC position and pump the fuel up for 10 to 15 seconds. However. If equipped electrical fuel feed pump. 3. Change the fuel hose together with the clamp every two years. 5. (When bleeding fuel (system) 1. 6. After the fuel hose and the clamp have been changed. The fuel hose (1) is made of rubber and ages regardless of the period service. Fill the tank with fuel and open the cock (4). apply oil to the threads and securely retighten
it. then change or remedy. (1) (2) (3) (4) (5) Fuel Hose Clamp Air Vent Plug Fuel Cock Air Vent Cock [A] Cartridge Type Element Type W1035921 G-11 KiSC issued 03. Loosen the air vent plug (3) of the fuel filter a few turns. If equipped mechanical fuel feed pump. ( only. if the fuel hose and clamp are found to be damaged or deteriorate earlier than two years. Close securely the air vent cock after air bleeding. CAUTION • Stop the engine when attempting the
check and change prescribed above. set the stop lever on stop position and crank the engine for 10 to 15 seconds.) 2. If the clamp (2) is loose. Screw back the plug when bubbles do not come up any more. 2. 3. or it may cause the engine to stop.G GENERAL SM-E3B SERIES WSM [3] CHECK POINT OF EVERY 50 HOURS Checking Fuel Hose 1. Q NOTE • Always keep the air vent cock on the fuel injection pump closed except when air is vented. Open the air vent cock
(5) on top of the fuel injection pump. 2011 A . 4. 4.
 
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