Kubota B2410D fitted with a D1105 engine.
Bear with me I’ll give as much info as possible so it will be a long post. Tractor is a friends.
Complaint was he would be cutting his grass and it would start to lose power after a few minutes of use, it would never cut out but would lose power. Sometimes he would switch it off then back on and it would be running rough, he also said when it happens he starts to get some smoke out of the exhaust.
My first thought was fuel starvation so went to have a look. The fuel supply to the filter is good, it pours out when you remove the fuel hose to the the filter, I removed the hose that goes from the filter to the mechanical lift pump and it pours out. I checked the filter which was good other than discolouration but put a new filter in anyway. The lift pump works as it should, I removed the fuel hose that goes from the lift pump to the injection pump and when cranking the engine it spurts out fuel as it should.
At this point I’m happy that it is not a fuel supply problem as such with regards to flow.
We ran the tractor and it was great for about 3 mins no problem then put the PTO on and it ran for a further 3 mins or so before it started to run poorly, I suspected at this time it was as if it was running on 2 cylinders. I started to open the fuel lines to the injector nozzles and when I cracked open the connector at cylinder No.1 the rpm’s did not drop, there was fuel when I opened it but it did not affect the running of the engine. I closed it off then cracked open cylinder no.2 and the rpm’s dropped and it was running rough, now running on 1. I repeated the same process for no.3 and the same thing happened, the rpms dropped and was running poorly now on 1.
At this point I suspected the injector nozzle on 1 to be faulty so we replaced that. The tractor ran great for about 3-5 minutes no probs then a further 6 minutes with the PTO on before doing the same as before. It was doing the same before with regards to cracking open the fuel lines except this time it had moved from 1 to 3, he had switched the tractor off and at one point it would not start, I cracked open the fuel lines again and there was no fuel, but there was fuel supply to the pump. So I removed the fuel cut off solenoid to rule that out and the tractor would still not start. I think in this moment it was just needing bled as I think ( trying to remember back ) I had removed one of the fuel lines, maybe checking the output from the lift pump again.
I was suspecting the injection pump at this point, so we got a reconditioned one and fitted that. I wasn’t convinced though as the one I removed the fuel rack was nice and loose working as it should and each plunger moved up and down as it should but he said to get one anyway. So with the new one fitted it’s doing the same.
I’m now fully convinced it’s drawing air in, but it seems to only do it after x amount of minutes, I’m wondering if the lift pump is drawing air in, I can’t see where else it could come from, all fuel lines are good and the return lines seem good, one is slightly deteriorated but not enough imho to cause any problems, I think I’ll replace that one anyway just to rule it out.
When it wouldn’t start and or was running very poorly towards the end and no matter how much I bled it it wouldn’t run any better, I was really starting to suspect air in the system at this point. Each time I cracked any lines there was visible bubbles and it just didn’t seem to improve. After shut down I removed the lift pump and when I removed the line from the pump to the injection pump there was a fair bit of gurgling and air noise, I’m not sure if this is just simply fuel returning back down from the pump and the return line or whether it’s a noise due to air getting drawn in.
This one has got me. Has anyone had experience with a lift pump where it’s been drawing air in even more so after it’s warmed up?
And for clarification, this tractor has fuel supply from tank to a fuel filter ( filter housing has no bleed screw, but a hose from the top that goes to the tank, then it goes to the mechanical lift pump ( no lever ) and then to the injection pump.
Cheers
Bear with me I’ll give as much info as possible so it will be a long post. Tractor is a friends.
Complaint was he would be cutting his grass and it would start to lose power after a few minutes of use, it would never cut out but would lose power. Sometimes he would switch it off then back on and it would be running rough, he also said when it happens he starts to get some smoke out of the exhaust.
My first thought was fuel starvation so went to have a look. The fuel supply to the filter is good, it pours out when you remove the fuel hose to the the filter, I removed the hose that goes from the filter to the mechanical lift pump and it pours out. I checked the filter which was good other than discolouration but put a new filter in anyway. The lift pump works as it should, I removed the fuel hose that goes from the lift pump to the injection pump and when cranking the engine it spurts out fuel as it should.
At this point I’m happy that it is not a fuel supply problem as such with regards to flow.
We ran the tractor and it was great for about 3 mins no problem then put the PTO on and it ran for a further 3 mins or so before it started to run poorly, I suspected at this time it was as if it was running on 2 cylinders. I started to open the fuel lines to the injector nozzles and when I cracked open the connector at cylinder No.1 the rpm’s did not drop, there was fuel when I opened it but it did not affect the running of the engine. I closed it off then cracked open cylinder no.2 and the rpm’s dropped and it was running rough, now running on 1. I repeated the same process for no.3 and the same thing happened, the rpms dropped and was running poorly now on 1.
At this point I suspected the injector nozzle on 1 to be faulty so we replaced that. The tractor ran great for about 3-5 minutes no probs then a further 6 minutes with the PTO on before doing the same as before. It was doing the same before with regards to cracking open the fuel lines except this time it had moved from 1 to 3, he had switched the tractor off and at one point it would not start, I cracked open the fuel lines again and there was no fuel, but there was fuel supply to the pump. So I removed the fuel cut off solenoid to rule that out and the tractor would still not start. I think in this moment it was just needing bled as I think ( trying to remember back ) I had removed one of the fuel lines, maybe checking the output from the lift pump again.
I was suspecting the injection pump at this point, so we got a reconditioned one and fitted that. I wasn’t convinced though as the one I removed the fuel rack was nice and loose working as it should and each plunger moved up and down as it should but he said to get one anyway. So with the new one fitted it’s doing the same.
I’m now fully convinced it’s drawing air in, but it seems to only do it after x amount of minutes, I’m wondering if the lift pump is drawing air in, I can’t see where else it could come from, all fuel lines are good and the return lines seem good, one is slightly deteriorated but not enough imho to cause any problems, I think I’ll replace that one anyway just to rule it out.
When it wouldn’t start and or was running very poorly towards the end and no matter how much I bled it it wouldn’t run any better, I was really starting to suspect air in the system at this point. Each time I cracked any lines there was visible bubbles and it just didn’t seem to improve. After shut down I removed the lift pump and when I removed the line from the pump to the injection pump there was a fair bit of gurgling and air noise, I’m not sure if this is just simply fuel returning back down from the pump and the return line or whether it’s a noise due to air getting drawn in.
This one has got me. Has anyone had experience with a lift pump where it’s been drawing air in even more so after it’s warmed up?
And for clarification, this tractor has fuel supply from tank to a fuel filter ( filter housing has no bleed screw, but a hose from the top that goes to the tank, then it goes to the mechanical lift pump ( no lever ) and then to the injection pump.
Cheers
