743 fuel issues

[Slave]

Hey Im new to the bobcat and this site, would appreciate any help. 743 sat for 7 yrs i did not drain the fuel maybe should have but added 5 gal of fresh with conditioner. pumped the bulb and fuel goes to bypass back to tank. pulled the rubber fuel line off the pump and it pulses but does not have a steady stream? i did not psi test yet? so removed the hard line at first injector and nothing after priming and cranking over. the fuel cutoff lever points away from stop but can that be faulty? take that apart? should fuel flow with primer bulb to the injector even if this was off? how painful is it to remove the injector pump and clean the guts out? thanx for ideas that will save me time

 

[Slave]

did i post this in the right place and was that too much info

 

[antfarmer2]

did i post this in the right place and was that too much info

Yep right place best bet would be a stuck fuel rack have never messed with one look up Tazza profile and email him

 

[Tazza]

Yep right place best bet would be a stuck fuel rack have never messed with one look up Tazza profile and email him

That fuel pulsing that you mention is normal.
It is possible the rack has stuck on the pump from sitting for a long time.
The best way is to pull the injector pump out. Take the inlet manifold for access. Remove the 6 or so bolts and slide it up. There is a notch in the block that a tang from the fuel rail slides through, make sure you line that up or it will not come out. When out ensure it slides freely, even give it a good oil. Put it back in, watch that the bar from the rail goes into the notch on the arm underneath. If not, the engine may start and run wide open till it pulls its self apart.
I can't remember exactly what was in there, there were springs from the throttle lever to the govenor, i can't remember what one gave better access, that cover or the fuel shut off cover to line the pump up....
Be careful not to lose the springs. There is one at one end of where the pump sits to push on the fuel rail, don't knock it down and into the sump.

 

[antfarmer2]

That fuel pulsing that you mention is normal.
It is possible the rack has stuck on the pump from sitting for a long time.
The best way is to pull the injector pump out. Take the inlet manifold for access. Remove the 6 or so bolts and slide it up. There is a notch in the block that a tang from the fuel rail slides through, make sure you line that up or it will not come out. When out ensure it slides freely, even give it a good oil. Put it back in, watch that the bar from the rail goes into the notch on the arm underneath. If not, the engine may start and run wide open till it pulls its self apart.
I can't remember exactly what was in there, there were springs from the throttle lever to the govenor, i can't remember what one gave better access, that cover or the fuel shut off cover to line the pump up....
Be careful not to lose the springs. There is one at one end of where the pump sits to push on the fuel rail, don't knock it down and into the sump.

Great info hopeing OM has pics

 

[Slave]

That fuel pulsing that you mention is normal.
It is possible the rack has stuck on the pump from sitting for a long time.
The best way is to pull the injector pump out. Take the inlet manifold for access. Remove the 6 or so bolts and slide it up. There is a notch in the block that a tang from the fuel rail slides through, make sure you line that up or it will not come out. When out ensure it slides freely, even give it a good oil. Put it back in, watch that the bar from the rail goes into the notch on the arm underneath. If not, the engine may start and run wide open till it pulls its self apart.
I can't remember exactly what was in there, there were springs from the throttle lever to the govenor, i can't remember what one gave better access, that cover or the fuel shut off cover to line the pump up....
Be careful not to lose the springs. There is one at one end of where the pump sits to push on the fuel rail, don't knock it down and into the sump.

the last time i pulled an injector pump was on a case backhoe years ago. i remember rolling it over to tdc on #1 for correct fuel timing when i put the rebuilt pump back in. I would like to know a good place to look for a shop manual or look at some pictures online, thank you for the help

 

[Tazza]

the last time i pulled an injector pump was on a case backhoe years ago. i remember rolling it over to tdc on #1 for correct fuel timing when i put the rebuilt pump back in. I would like to know a good place to look for a shop manual or look at some pictures online, thank you for the help

Kubota engines run an inline pump, no timing is required. It has a cam shaft under it that does the timing, the fine tuning is done with shims under the pump. Just put the same amount back when you put the pump back on.

 

[Slave]

Kubota engines run an inline pump, no timing is required. It has a cam shaft under it that does the timing, the fine tuning is done with shims under the pump. Just put the same amount back when you put the pump back on.

Thanx for the info I pulled the four bolts off the manual fuel cutoff and pushed the lever back with a screw driver and some juicy spray and worked it a bit and it sounds smooth when running. I got lucky. not knowing bobcats other than complete fluid and filter change with a lube job at 3800 hours are there things not obvious i should look at for preventative costs? dont know

 

[antfarmer2]

Thanx for the info I pulled the four bolts off the manual fuel cutoff and pushed the lever back with a screw driver and some juicy spray and worked it a bit and it sounds smooth when running. I got lucky. not knowing bobcats other than complete fluid and filter change with a lube job at 3800 hours are there things not obvious i should look at for preventative costs? dont know

The most over looked and costly if they fail is the u-joints that go from the engine to the pump a hundred bucks and a afternoon to replace a pita to grease

 

[antfarmer2]

The most over looked and costly if they fail is the u-joints that go from the engine to the pump a hundred bucks and a afternoon to replace a pita to grease

Did you do the chaincase fluid?

 

[Slave]

Did you do the chaincase fluid?

ok u-joints and chain fluid, the chain fluid sounds easy, ill get a cooler ready when i go after the u-joint, i did tip the cab when the quick coupler aux didnt work my buddy didnt have any implements so that valve didnt move for fifteen years with only a bucket, i tapped it with a rod and hammer back and forth until the grapple bucket i got works i replaced the pioneer with flat fittings so i could use newer stuff my other friends have i could not imagine what that would have been like taking that apart down there if that valve was still stuck. do i need to go in there to align the u-joint or do i get a monkey to go in the engine compartment? maybe it looks worse than it is because i dont know the territory. thanks for the info, ill end up doing the joint anyway

 

[antfarmer2]

ok u-joints and chain fluid, the chain fluid sounds easy, ill get a cooler ready when i go after the u-joint, i did tip the cab when the quick coupler aux didnt work my buddy didnt have any implements so that valve didnt move for fifteen years with only a bucket, i tapped it with a rod and hammer back and forth until the grapple bucket i got works i replaced the pioneer with flat fittings so i could use newer stuff my other friends have i could not imagine what that would have been like taking that apart down there if that valve was still stuck. do i need to go in there to align the u-joint or do i get a monkey to go in the engine compartment? maybe it looks worse than it is because i dont know the territory. thanks for the info, ill end up doing the joint anyway

You can grease them from under the cage if you lie on the pump and reach in on the right they are three fittings to grease I just replaced mine any vibration shut it down it can do some major damage.....to get the chaincase clean you will need to get in there and mop it out with rags I put some earth magnets in to keep the metal away.....I would also check the wheel bearing pick it up pull and lift one the tire should be no play rotate the tire front and back about inch and a half before the other tire moves.......my aux hydro is stuck too did not notice untill I put it back together how did you tap it back and forth worth a try

 

[antfarmer2]

You can grease them from under the cage if you lie on the pump and reach in on the right they are three fittings to grease I just replaced mine any vibration shut it down it can do some major damage.....to get the chaincase clean you will need to get in there and mop it out with rags I put some earth magnets in to keep the metal away.....I would also check the wheel bearing pick it up pull and lift one the tire should be no play rotate the tire front and back about inch and a half before the other tire moves.......my aux hydro is stuck too did not notice untill I put it back together how did you tap it back and forth worth a try

You will need a long hose to grease the u-joints .....about a hundred bucks at loaderpartsource but pay attention four of the bolts were to long and would put it in a bind and use blue locktight ......I pulled the rad oil cooler and the muffler with the metal plate not to hard but a bit heavey and gave it a good cleaning there are two hidden bolts on either side by the tanks that hold the metal plate in much easyer to put the engin back in with it out then only two bolts to pull the shrould pull it and give a good cleaning........just to the right of center on the bottom there are two steel lines that cross at a ninty they fail there wedge a piece of rubber there and shoot some good rust paint after cleaning on the steel lines

 

[Slave]

You can grease them from under the cage if you lie on the pump and reach in on the right they are three fittings to grease I just replaced mine any vibration shut it down it can do some major damage.....to get the chaincase clean you will need to get in there and mop it out with rags I put some earth magnets in to keep the metal away.....I would also check the wheel bearing pick it up pull and lift one the tire should be no play rotate the tire front and back about inch and a half before the other tire moves.......my aux hydro is stuck too did not notice untill I put it back together how did you tap it back and forth worth a try

the aux was stuck i believe from not being used. if you open the cage and look at the pivot point of the right stick you will see the rod going back to the valve body. i had a scrap of 1/2"x3' steel rod that went from outside through the boot and centered it on that connecting rod and had someone hit it until i felt it move just a bit while holding the control. then went to the other side and tapped it back slowly until it freed up and back and fourth easy until it worked loose it moves freely and doesnt leak so go slow maybe that is not the right way to do it but look down there, the options looked a bit time consuming, thought it worth a try, good luck worked for me?

 

[antfarmer2]

the aux was stuck i believe from not being used. if you open the cage and look at the pivot point of the right stick you will see the rod going back to the valve body. i had a scrap of 1/2"x3' steel rod that went from outside through the boot and centered it on that connecting rod and had someone hit it until i felt it move just a bit while holding the control. then went to the other side and tapped it back slowly until it freed up and back and fourth easy until it worked loose it moves freely and doesnt leak so go slow maybe that is not the right way to do it but look down there, the options looked a bit time consuming, thought it worth a try, good luck worked for me?

Ok will oil it up and give it a go thank you Ant

 

[Tazza]

Ok will oil it up and give it a go thank you Ant

You were lucky that the rack freed up. When the engine runs, it splashes oil all over the place, that prevents it sticking.
I like the idea of chain case and u-joints. THe u-joints aren't too bad to work on/replace. Removing the engine isn't too bad if you have a helper, it allows you to clean it out a bit more too.
Clean the radiator and oil cooler out, hydro/air filter too.
When you do the chain case, drain the hydro fluid into the chain case. It is meant to be done every 1,000 hours but works just fine in a chain case if it's not milky.