743 bobcat starter

[mkueffler]

i have a 743 bobcat. i have been having problems with it loosing power all the sudden. it would almost die and then when i would let of the hydrolics it would recover. also if i bang into something like a curb with the bucket it will almost kill the engine. now that winter is here it has been acting up like it is gelling up. it finaly died and wouldnt restart so i put some 911 anti gel in a new filter and started it, it fired right up and ran for a couple minutes then died, now it wont turn over, its like the starter quit working or something. battery is good. i get a click and that is it. does anyone have any ideas?

 

[bremery]

I am not sure about your fuel problem, but I would suggest pulling the starter and looking at the solenoid on the starter. If I remember correctly there is a plunger that gets pushed up against an electrical contact to power the starter. On my old 743 this had worn out and you could tell it was not making contact. It would click though. I was able to apply power directly to the starter to make sure it was ok. I ended up getting a new solenoid and had no problems from there.

 

[mkueffler]

I am not sure about your fuel problem, but I would suggest pulling the starter and looking at the solenoid on the starter. If I remember correctly there is a plunger that gets pushed up against an electrical contact to power the starter. On my old 743 this had worn out and you could tell it was not making contact. It would click though. I was able to apply power directly to the starter to make sure it was ok. I ended up getting a new solenoid and had no problems from there.

thanks, I have pulled the starter off and will check it out. hopefuly someone can help me with the engine bogging down and dying problem to!

 

[Tazza]

thanks, I have pulled the starter off and will check it out. hopefuly someone can help me with the engine bogging down and dying problem to!

Its possible its a loss of luft pressure to the injector pump. Does it do it often?
if you can load it down, get someone to squeeze the primer bulb, see if it revs back up. This is the same as giving it a bit more fuel pressure.

 

[mkueffler]

Its possible its a loss of luft pressure to the injector pump. Does it do it often?
if you can load it down, get someone to squeeze the primer bulb, see if it revs back up. This is the same as giving it a bit more fuel pressure.

no not a lot Tazza, but more all the time it seems. i bought a new pickup tube and screen today and will install that. the starter was bad, no brushes left what so ever i guess, i had it completly rebuilt so tomorrow I will put it all together and see how it goes

 

[mkueffler]

no not a lot Tazza, but more all the time it seems. i bought a new pickup tube and screen today and will install that. the starter was bad, no brushes left what so ever i guess, i had it completly rebuilt so tomorrow I will put it all together and see how it goes

ok after installing the rebuilt starter it works great, now I still cant get it to run. here is what Ive checked fuel is getting all the way to the injectors. its spirts out the fuel filter bleed valve, ive unhooked line after the pump and it surges out the hose ( i expected it to shoot out a few feet but it only rose a 1/4 inch and come out) i cracked open the injectors and fuel pulses out them. whats happening is i pre heat and the thing will start and run for about 6 seconds and die, it keeps doing this. at one point once it started i quickly turned on the pre heat and it kept runing until i let of the pre heat. white smoke is coming out the exhaust, no black, but its not really running good when it does start and run for 6 seconds. i ordered a new pump (one on top back left side of enging by injectors) in hopes that is the problem in that its not getting enough fuel. any thoughts from anybody on this would be greatly appriciated

 

[Tazza]

ok after installing the rebuilt starter it works great, now I still cant get it to run. here is what Ive checked fuel is getting all the way to the injectors. its spirts out the fuel filter bleed valve, ive unhooked line after the pump and it surges out the hose ( i expected it to shoot out a few feet but it only rose a 1/4 inch and come out) i cracked open the injectors and fuel pulses out them. whats happening is i pre heat and the thing will start and run for about 6 seconds and die, it keeps doing this. at one point once it started i quickly turned on the pre heat and it kept runing until i let of the pre heat. white smoke is coming out the exhaust, no black, but its not really running good when it does start and run for 6 seconds. i ordered a new pump (one on top back left side of enging by injectors) in hopes that is the problem in that its not getting enough fuel. any thoughts from anybody on this would be greatly appriciated

That is your lift pump. If you grab the primer bulb and squeeze it, it will give you higher pressure and if it comes good it could be the lift pump.
As you say you need to try and start and keep it going with the plugs on leads me to think your problem is injector related or low compression.... Do you have access to a compression tester by any chance? the pressure should be around 400PSI

 

[mkueffler]

That is your lift pump. If you grab the primer bulb and squeeze it, it will give you higher pressure and if it comes good it could be the lift pump.
As you say you need to try and start and keep it going with the plugs on leads me to think your problem is injector related or low compression.... Do you have access to a compression tester by any chance? the pressure should be around 400PSI

yes i can get a compresson tester, I will check them and see what i get. are you thinking a blow head gasget, bad rings or hole in a piston?

 

[Tazza]

yes i can get a compresson tester, I will check them and see what i get. are you thinking a blow head gasget, bad rings or hole in a piston?

Possibly low compression due to age, or your valves are sticking open slightly. You did mention it will fire when the plugs are left on, it could even be a bad spray pattern from the injectors.
Start with the compression, then work back from there. Remember to keep the stop cable pulled, if it fires, you will destroy the tester. Not sure what the easiest way to install the tester would be too, i'm pretty sure i pulled my injectors, removing the glow plugs didn't give much access due to the fact the inlet manifold was in the way....
With the injectors out, you can give them a quick test, install a tube line from the pump out the back of the door, attach an injector and crank, look at the spray, it should be a narrow cone, no droplets should form on the end either. It should be a nice even spray.

 

[Tazza]

yes i can get a compresson tester, I will check them and see what i get. are you thinking a blow head gasget, bad rings or hole in a piston?

Hopefully that makes a little sense.

 

[mkueffler]

Hopefully that makes a little sense.

the fuel pump i ordered will be here on friday and i will install that and hope to the bobcat gods that is the problem. if not i will follow your directions on checking cylinder presure, a couple months ago i had it into the dealership to fix a blow hydrolic line and they stated it looked like the injectors were new. thanks for your help, I appriciate it!

 

[Tazza]

the fuel pump i ordered will be here on friday and i will install that and hope to the bobcat gods that is the problem. if not i will follow your directions on checking cylinder presure, a couple months ago i had it into the dealership to fix a blow hydrolic line and they stated it looked like the injectors were new. thanks for your help, I appriciate it!

Hopefully that is all it is, let me know how you go.

 

[mkueffler]

Hopefully that is all it is, let me know how you go.

I put the new fuel pump on and tried to start it. it didnt go at first so the second try when it fired I turned the key to preheat, it kept running and after a moment it was like a second cylinder caught, then another and finaly it took off running just fine. I moved snow for two hours with it and it runs better than it ever has. tried starting it the next day and if started right up, so it seems to be fixed, thanks for your help!