Oil & Fuel Starting after fuel filter replacement

[SalisburySenior]

I have a 1983 Kubota M6950DT. I have just replaced the fuel filter and after a couple of seconds of running, the engine stopped. I've cranked the engine for some time and now have the battery charger recharging the battery. How long does it take to purge the air from the system? Is there some technique I should be doing other than cranking the engine? I have the factory manual, but it simply says to unscrew the bolt on top and replace the filter cartridge. No hints on how to purge the air from the system and get the tractor running again. I'd appreciate any help you may be able to provide.

 

[bironacad]

Last month my tractor got the 100 hour service, part of that service was to replace all filters including the fuel filter. Same deal happened when the mechanic tried to start it, so he cracked a couple of lines going to the injectors turned the key let it bleed re cranked them tight an away she went. My truck CTD (Dodge) I just turn the key a couple of times without engaging the engine, you here the pump going and it purges itself, not so on my tractor it seems it does not have the same presquirt deal, lol. Hope this helps.:thumbsup:

 

[9973720wb19]

don't have a Kubota but my tractor has a small black pump on the top of the fuel filter that you have to push about 10 - 15 times to prime the fuel and get the air out - it also has a little bleeder valve on the side. in the future it helps to fill the new filter with diesel before you install...other than that, some tractors are self priming.

 

[Farmerford]

Loosen the nut on the fuel injection pump end of each line from the pump to the fuel injectors about a half turn.

Crank with the starter until bubble free fluid comes out around the end of each line. Should not take more than a few seconds.

Tighten those nuts and loosen the nuts at the fuel injector ends of the lines (on the cylinder head).

Crank with the starter until bubble free fuel flows out around the end of each line.

Tighten those nuts. Crank with the starter and after a very few seconds it should start. May run rough for a minute or so in one or more of the lines has air in it.

If it continues to run rough, let it run, but loosen the nuts on the fuel injector end of the lines one line at the time. If a nut on a fully primed line is loosened, bubble free fuel will come out and the engine will get rougher because you have disabled a working fuel injector. Tighten that one back.
Loose the rest individually and retighten after clean fuel comes out. You should be running on all four (?) cylinders.

 

[SalisburySenior]

Thanks to all who provided helpful suggestions on purging air from the fuel system. Work on the tractor has been delayed as the rains from Tropical Depression Lee have arrived. The pause has given me a chance to break out the tractor manuals and I found the "official" purge procedure in one of the manuals. (When all else fails, read the manual). All of the above suggestions are very similar to the Kubota procedure. It all looks simple on paper, but the loader framework blocks much of the access to the engine compartment, so the procedure will be a challenge. Thanks again to all who replied!

 

[mguitas]

I have a 1983 Kubota M6950DT. I have just replaced the fuel filter and after a couple of seconds of running, the engine stopped. I've cranked the engine for some time and now have the battery charger recharging the battery. How long does it take to purge the air from the system? Is there some technique I should be doing other than cranking the engine? I have the factory manual, but it simply says to unscrew the bolt on top and replace the filter cartridge. No hints on how to purge the air from the system and get the tractor running again. I'd appreciate any help you may be able to provide.

I was thinking of doing the same you were doing, but i was afraid the massey would not start. Let me know how it works out.

 

[SalisburySenior]

I'll leave a post on this thread when I am finished. I have to work on the tractor outside, so it will be a day or two before the storms pass through and the ground drains off a little.

 

[PHILIP8N]

You are not suppose to do this, but I pre-fill the new fuel filter with fuel before installing it. Have done this many times and never had to purge the high pressure side of air. Why don't you pre-fill filters? Some of the fuel poured in filter will not be filtered that goes to the injectors. As long as you use clean fuel, clean containers, and work in a clean environment, your risk is very low. Philip.

 

[SalisburySenior]

Philip - Sounds like a good idea for your tractor. My tractor has a filter element sandwiched between a bottom cap and a top cap. The filter element is open at the top and bottom, so any fuel poured in would drain out. To further complicate matters, the pieces (filter element and bottom cap) have to be moved in various directions as they are installed because of obstacles such that any fuel added (even if the joint between the bottom cap and element didn't leak) would be poured out. The Kubota procedure is basically a progressive venting routine, starting at the filter top cap and ending at the injectors. A total of 7 venting points. Somewhat a PITA.

 

[gabeancounter]

Just did my Massey 1040. Had the same thing happen. Yes, I did bleed until diesel came out the top bleeder. I just kept rapidly pumping the gas pedal while it was cranked. This took about 60-90 seconds of constant pumping then it ran fine. The whole time it was wanting to go dead, but kept pumping the pedal.

Reminds me of my dads old 69 GMC pickup..lol

 

[MHarryE]

My newer Kubota (newer meaning purchased new in April) has a bleed vent on top of the filter housing. Sounds like they made an improvement since the older models. I was 8 miles from home the other day when my panel read low fuel. I was about 1/2 mile from home when I ran out and had to call my wife to bring fuel and the manual. I thought I would have a big problem but it started quickly, then stopped. Started quickly again, sputtered a few seconds, and then ran smooth. It said to close the bleed valve after 30 seconds so I did and it was run fine ever since. Lesson learned - the gauge on my tractor means empty when it says empty, and doesn't give a lot of reserve like all of my other vehicles.

Different engines have different bleed techniques. The newest common rail systems with extremely high pressure are generally self priming. I know on some of the engines you are required to replace any of the injector lines if you take them loose because they will never reseal for the 30,000 psi seen on some of the new systems. I wonder what will happen on those systems in 30 years when the manuals have been eaten by mice and somebody has to figure out how to bleed a system.

 

[Tx Jim]

An over the road truck driver taught me a lesson on filling fuel filter upon replacement of fuel filter to just fill the filter or filters with trans fluid. It's worked for me since the 1970's. Pouring trans oil out of a qt bottle into a filter is much easier than diesel out of a can.

 

[SalisburySenior]

SUCCESS! I was only able to bleed 4 of the Kubota recommended 7 places because of congestion around the engine, but that was enough to get the engine started again.

 

[bironacad]

Good stuff my engine is the same for getting at if there was no loader it would be easier access, go figure.

 

[leonz]

My newer Kubota (newer meaning purchased new in April) has a bleed vent on top of the filter housing. Sounds like they made an improvement since the older models. I was 8 miles from home the other day when my panel read low fuel. I was about 1/2 mile from home when I ran out and had to call my wife to bring fuel and the manual. I thought I would have a big problem but it started quickly, then stopped. Started quickly again, sputtered a few seconds, and then ran smooth. It said to close the bleed valve after 30 seconds so I did and it was run fine ever since. Lesson learned - the gauge on my tractor means empty when it says empty, and doesn't give a lot of reserve like all of my other vehicles.

Different engines have different bleed techniques. The newest common rail systems with extremely high pressure are generally self priming. I know on some of the engines you are required to replace any of the injector lines if you take them loose because they will never reseal for the 30,000 psi seen on some of the new systems. I wonder what will happen on those systems in 30 years when the manuals have been eaten by mice and somebody has to figure out how to bleed a system.

All the more reason for Kubota to buy the AVCO/Duetz engine patents and start making air coolled diesels as they are the least troublesome to
own and operate.

 

[JoeL4330]

I am guessing that your tank is above your filter and pump, so getting fuel to it is not problem, but you might file away a solution I came up with on my VW Jetta TDI: rather than try to draw a vacuum from the tank to the filter, I used a shop vacuum in reverse--with a rag around it to seal it--and then gently pressurized the fuel tank, which sent a good flow of diesel up to the filter.

Should also mention that I had an out-of-fuel condition on my Kubota but I knew to immediately shut it down and not try to restart a few time (despite the temptation) until I refilled the tank...and, it self-primed.

Another time, my dealer-mechanic changed the filter and lost the prime and it required all the tricks mentioned above: cracking the injectors and opening the bleed valve and cranking away a number of times ...REMEMBER not to crank the starter continuously for too long a time...honoring the recommended duty-cycle is the key to not burning out the starter motor

 

[SalisburySenior]

I am guessing that your tank is above your filter and pump, so getting fuel to it is not problem, but you might file away a solution I came up with on my VW Jetta TDI: rather than try to draw a vacuum from the tank to the filter, I used a shop vacuum in reverse--with a rag around it to seal it--and then gently pressurized the fuel tank, which sent a good flow of diesel up to the filter.

Should also mention that I had an out-of-fuel condition on my Kubota but I knew to immediately shut it down and not try to restart a few time (despite the temptation) until I refilled the tank...and, it self-primed.

Another time, my dealer-mechanic changed the filter and lost the prime and it required all the tricks mentioned above: cracking the injectors and opening the bleed valve and cranking away a number of times ...REMEMBER not to crank the starter continuously for too long a time...honoring the recommended duty-cycle is the key to not burning out the starter motor

Joel - Your are correct, the tank is above the pump and filter. The shop vacuum in reverse is certainly one way to move the fuel to the filter. The owner's manual I have recommends pressing on the lever on the fuel pump to manually pump diesel to the filter and beyond (with vents cracked). It seemed to work.

I agree on not trying to restart the engine without first purging the air after changing the fuel filter. Unfortunately I learned the hard way and did try to start the engine right after installing the new filter. The engine started and ran for about three seconds and then quit. I just made my purging job a little more difficult.