texasjohn
Super Member
Ok... well, I learned something, thought I'd pass it on.
Tractor was running purrrrfectly dandy but I knew the low fuel light was on. It was also leaking slowly at the fuel filter... bad O ring gasket. Making a mess and costing $$.
I replaced the gasket... pennies from the Kubota dealer which mailed it to me. Actually, there are two O ring gaskets... one large one around the top of the clear plastic bowl and another smaller one that fits over the tube that fits down inside the fuel filter.
So, according to the manual, I opened the air vent valve to allow air in the line/fuel bowl to escape and made sure the fuel shut off was ON so it would get fuel. As has happened on previous occasions when replacing the fuel filter, it started IMMEDIATELY and ran fine for maybe 30 seconds, then started running rough, then rougher, then stopped and would not start. First time the tractor has not run perfectly in 500+ hrs.
Hmm.....opened the fuel cap and looked in... yep.... bottom of tank visible.
Installed 5 gallons of diesel ..... tried to crank..... with air vent valve open... still no joy. Numerous tries, over several days, trying various combinations of valves open/closed, kept trickle charger on battery and never ran starter enough to get it overheated. Simply no effort to run but always cranked at good rate.
Finally, got a buddy to help me... he sat in the seat and cranked for brief intervals ... he didn't have a golden touch, either I started opening fuel lines at various points to see if fuel was getting there. Air vent valve is open. He would crank while I wrenched it.
First, opened the fitting right at the injector...on top of the engine... a bare wetness of fuel came out... no extra when cranking. Note.... getting on top of the engine to see this fitting and a wrench on it requires some major contortions! Lots of head scratching and following of fuel lines from filter to pump... there are two devices... seems to be a gravity fed fuel pump which feeds an injector pump.
So, I went to the output line of the fuel pump (it was the easiest to get to) and undid the clamp on the rubber hose and backed the hose off of the pump. Cranking got air and bubbly fuel which I let dribble out until no more bubbles, then I reappled the hose and clamp.
Cranking now got it to run rough for a second or so, then stop. Air valve is open. Crank, run, stop..... crank, run... stop.... repeat, repeat.... Probably for about 5 minutes with periods of rest to prevent overheating starter. then, finally, it began to run for a little longer... then a little longer... then finally it kept running when key was released... rough.... then a little stronger, then almost smooth.... then it was purring
Conclusion... replacing the fuel filter is a breeze and vehicle will restart fine using the air valve.
Run the sucker out of fuel.... the air valve is ineffective in removing air and fuel lines must be followed and proven to be supplying fuel.
I know, elemental, but I put my faith in the air valve too long.... and, now I know to NEVER run out of fuel again
Hope you never need to do this, but if you do, hope you remember this and that it helps! Oh, yes... it helps to have a buddy to talk things thru with and turn the crank.... while you observe what is happening... even a 10 year old kid might work!
Tractor was running purrrrfectly dandy but I knew the low fuel light was on. It was also leaking slowly at the fuel filter... bad O ring gasket. Making a mess and costing $$.
I replaced the gasket... pennies from the Kubota dealer which mailed it to me. Actually, there are two O ring gaskets... one large one around the top of the clear plastic bowl and another smaller one that fits over the tube that fits down inside the fuel filter.
So, according to the manual, I opened the air vent valve to allow air in the line/fuel bowl to escape and made sure the fuel shut off was ON so it would get fuel. As has happened on previous occasions when replacing the fuel filter, it started IMMEDIATELY and ran fine for maybe 30 seconds, then started running rough, then rougher, then stopped and would not start. First time the tractor has not run perfectly in 500+ hrs.
Hmm.....opened the fuel cap and looked in... yep.... bottom of tank visible.
Installed 5 gallons of diesel ..... tried to crank..... with air vent valve open... still no joy. Numerous tries, over several days, trying various combinations of valves open/closed, kept trickle charger on battery and never ran starter enough to get it overheated. Simply no effort to run but always cranked at good rate.
Finally, got a buddy to help me... he sat in the seat and cranked for brief intervals ... he didn't have a golden touch, either I started opening fuel lines at various points to see if fuel was getting there. Air vent valve is open. He would crank while I wrenched it.
First, opened the fitting right at the injector...on top of the engine... a bare wetness of fuel came out... no extra when cranking. Note.... getting on top of the engine to see this fitting and a wrench on it requires some major contortions! Lots of head scratching and following of fuel lines from filter to pump... there are two devices... seems to be a gravity fed fuel pump which feeds an injector pump.
So, I went to the output line of the fuel pump (it was the easiest to get to) and undid the clamp on the rubber hose and backed the hose off of the pump. Cranking got air and bubbly fuel which I let dribble out until no more bubbles, then I reappled the hose and clamp.
Cranking now got it to run rough for a second or so, then stop. Air valve is open. Crank, run, stop..... crank, run... stop.... repeat, repeat.... Probably for about 5 minutes with periods of rest to prevent overheating starter. then, finally, it began to run for a little longer... then a little longer... then finally it kept running when key was released... rough.... then a little stronger, then almost smooth.... then it was purring
Conclusion... replacing the fuel filter is a breeze and vehicle will restart fine using the air valve.
Run the sucker out of fuel.... the air valve is ineffective in removing air and fuel lines must be followed and proven to be supplying fuel.
I know, elemental, but I put my faith in the air valve too long.... and, now I know to NEVER run out of fuel again
Hope you never need to do this, but if you do, hope you remember this and that it helps! Oh, yes... it helps to have a buddy to talk things thru with and turn the crank.... while you observe what is happening... even a 10 year old kid might work!