443 bobcat problem, stumped.. plz help!

[443life]

hello everyone, looking to get some help/suggestions from anyone who has some experience with this model.. its a 443 powered by a kubota d750, a few days ago it started blowing a bit of blue smoke, nothing major so i didnt think much of it as its an old machine. then it just lost power and died all of a sudden. i can start it on idle after ive primed the fuel but once i turn it to WOT and try to operate it it will die again , either under load or while its in WOT for a few minutes. at first i thought it may be a scored piston ring because of the blue smoke, if i prime it sometimes i can turn it to WOT and itll run but once its under load itll die again so im kind of stumped as to wether or not it may be a fuel delivery problem or something more major. iv'e drained the tank and put fresh diesel in it to possibly eliminate contaminants in the fuel, i changed the air filter, checked all the fuel lines but havent changed the fuel filter yet as i am waiting for one still, is there something small i may be overlooking that may be causing this? any help is appreciated, thanks!

 

[SkidRoe]

This is just a guess, but something that should be looked at while you are eliminating possibilities: check the fuel line in the tank, if you have not already. Your machine is of the age where failure of this tube is a common occurrence.
My $0.02 - SR

 

[Tazza]

This is just a guess, but something that should be looked at while you are eliminating possibilities: check the fuel line in the tank, if you have not already. Your machine is of the age where failure of this tube is a common occurrence.
My $0.02 - SR

Blue smoke sounds like engine oil, not a good sign i'm afraid.
Will it run smoke free at idle?
If the primer bulb gets sucked flat when running, you have a restirction, but i wouldn't expect to see smoke, it would usually just slow down and stall on you.
Not sure how the breather is plumbed on this model, but if there was a crack or something, allowing excessive by-pass, you could be blowing oil through this tube backinto the inlet of the engine.

 

[443life]

This is just a guess, but something that should be looked at while you are eliminating possibilities: check the fuel line in the tank, if you have not already. Your machine is of the age where failure of this tube is a common occurrence.
My $0.02 - SR

Hi guys, thanks for the replies, so a little update after i changed the diesel and ran it for a good hour it seemed to run okay then outta nowhere the bolts securing the muffler to the manifold both snapped so ive had to tap them out and put some grade 6 bolts in then the very next day my exhaust tip on the muffler decides to break off and ive got a cab full of diesel smoke.. not cool so i guess ive gotta get a new muffler fabricated (bobcat does not make anymore) before i can start er up. SkidRoe do you have any idea what year my machine may be? or is there a way to tell? i will take you up on that and check the fuel lines you are right everything is wearing out on it but its still a great machine very easy to work on! and Tazza i did not notice much blue smoke or any at all once i had it running again just abit when it was cold then once it warmed up there was no noticeable smoke so you may be right on that because i noticed there is a tube on the top of the valve cover was blowing a bit of smoke out of it.. is that the tube you are referring to? also another question for you guys my hydraulic control valve sprung a leak where the seals are so i rebuilt the control valve and reassembled everything i have a slight chatter when i use the lift arms, there is a small leak on my tilt cylinder would that cause it? or is it an entirely different problem? my father's a mechanic i grew up fixing cars but diesel/hydraulics is a bit more complicated to me hence the questions, thanks guys !

 

[Arik434]

Hi guys, thanks for the replies, so a little update after i changed the diesel and ran it for a good hour it seemed to run okay then outta nowhere the bolts securing the muffler to the manifold both snapped so ive had to tap them out and put some grade 6 bolts in then the very next day my exhaust tip on the muffler decides to break off and ive got a cab full of diesel smoke.. not cool so i guess ive gotta get a new muffler fabricated (bobcat does not make anymore) before i can start er up. SkidRoe do you have any idea what year my machine may be? or is there a way to tell? i will take you up on that and check the fuel lines you are right everything is wearing out on it but its still a great machine very easy to work on! and Tazza i did not notice much blue smoke or any at all once i had it running again just abit when it was cold then once it warmed up there was no noticeable smoke so you may be right on that because i noticed there is a tube on the top of the valve cover was blowing a bit of smoke out of it.. is that the tube you are referring to? also another question for you guys my hydraulic control valve sprung a leak where the seals are so i rebuilt the control valve and reassembled everything i have a slight chatter when i use the lift arms, there is a small leak on my tilt cylinder would that cause it? or is it an entirely different problem? my father's a mechanic i grew up fixing cars but diesel/hydraulics is a bit more complicated to me hence the questions, thanks guys !

SkidRoe is the expert on these machines, so I'll let him chime in, but if you had your control valve apart, and now you are getting a chatter, its probably air in your lines. The lift cylinders on my 440 are due for a rebuild as well--they seep a little bit, but it doesn't seem to affect the operation at all.

 

[Tazza]

SkidRoe is the expert on these machines, so I'll let him chime in, but if you had your control valve apart, and now you are getting a chatter, its probably air in your lines. The lift cylinders on my 440 are due for a rebuild as well--they seep a little bit, but it doesn't seem to affect the operation at all.

That is the tube i was talking about.
I agree that the chatter should just be air in the system, hopefully it will settle out. It can take a few days for it to all be purged.
A leaky cylinder could draw in air, but i'd doubt it would be enough to do this.