Bobcat 743B

[Stonemtn]

I have a 743B Bobcat. A few months back it wouldn't start. No or very little fuel was getting to the injectors. Mechanic pulled the injector pump- had it rebuilt and said the fuel rack was stuck. $750 dollars later, it ran fine. A week or so ago, it would not start again. Same symptoms- very little fuel getting to the injectors. Called him and he said the rebuilt pumps are notorious for the fuel rack sticking and suggested we purchase a brand new injector pump. My question- if this is correct- can I remove the fuel solenoid and free up the rack myself without having to remove the injector pump . Any advice would be greatly appreciated.

 

[Tazza]

That doesn't sound rite to me.
I'd start by getting a jug of fuel, disconnect the fuel line before the hand primer and attach a piece of fuel hose from the jug of fuel to the hand primer. Replace the fuel filter for good measure too. Open the bleed screw to get the air out, close the screw and see if it will start.
Even tie the stop solenoid back so you know it's in the run position.
I'd suspect the pickup tube in the fuel tank is to blame, but using a jug of fuel will isolate the main fuel tank.

 

[dschoolman]

That doesn't sound rite to me.
I'd start by getting a jug of fuel, disconnect the fuel line before the hand primer and attach a piece of fuel hose from the jug of fuel to the hand primer. Replace the fuel filter for good measure too. Open the bleed screw to get the air out, close the screw and see if it will start.
Even tie the stop solenoid back so you know it's in the run position.
I'd suspect the pickup tube in the fuel tank is to blame, but using a jug of fuel will isolate the main fuel tank.

I would definitely check the pickup. Before I tore down my 743 for rebuild, I had a heck of a time getting it started. Sometimes it would start and seemed to run fine. Then nothing. I followed it back to the pickup. It was all gunked up.

 

[JPL]

The pickup hose end just sits on the bottom of the tank and gets plugged. This has happen to me 2x's. You need to pull the hose up from the top of the tank then pull the opposite end off and blow air through it. Removing the top plate makes it easier to pull the hose. You will be surprised at the slimy crap that will come out. Another interdiction that the hose is blocked is the squeeze ball near the filter will collapse and not go back to original shape right away. hope this helps.

 

[Stonemtn]

The pickup hose end just sits on the bottom of the tank and gets plugged. This has happen to me 2x's. You need to pull the hose up from the top of the tank then pull the opposite end off and blow air through it. Removing the top plate makes it easier to pull the hose. You will be surprised at the slimy crap that will come out. Another interdiction that the hose is blocked is the squeeze ball near the filter will collapse and not go back to original shape right away. hope this helps.

The pickup seems to be free of obstruction. I'm told the fuel rod may be sticking. Am I going to need to remove the fuel pump or injector pump in order to free up the fuel rod? I've isolated the fuel from the tank w a jug- the fuel flows fine confirming its not the pickup tube in the tank. Thanks for all your help guys!

 

[antfarmer2]

The pickup seems to be free of obstruction. I'm told the fuel rod may be sticking. Am I going to need to remove the fuel pump or injector pump in order to free up the fuel rod? I've isolated the fuel from the tank w a jug- the fuel flows fine confirming its not the pickup tube in the tank. Thanks for all your help guys!

Like Tazza said make sure the bleeder valve is shut after bleeding.........I just bought a new bleeder valve for my 743 because it was sucking air bobcat told me I had to for 30 bucks did not evan kiss me first replaced it then took the old one apart and found a two cent o ring was cracked

 

[Stonemtn]

Like Tazza said make sure the bleeder valve is shut after bleeding.........I just bought a new bleeder valve for my 743 because it was sucking air bobcat told me I had to for 30 bucks did not evan kiss me first replaced it then took the old one apart and found a two cent o ring was cracked

Will do . Thanks for all the help guys. The bleeder screw o-ring tip may just be the culprit. You guys are the best!!!!

 

[antfarmer2]

Will do . Thanks for all the help guys. The bleeder screw o-ring tip may just be the culprit. You guys are the best!!!!

Does yours have a fuel shut off lever or a soliniod?

 

[antfarmer2]

Does yours have a fuel shut off lever or a soliniod?

Ok reread wire your soliniod back to open might work if not follow the little injector lines back to the back of the engine pull that line off and see if fuel is comming out if so pull the line off the bleeder and pump the rail with marvel mystry oil or something close let it sit over nite

 

[antfarmer2]

Ok reread wire your soliniod back to open might work if not follow the little injector lines back to the back of the engine pull that line off and see if fuel is comming out if so pull the line off the bleeder and pump the rail with marvel mystry oil or something close let it sit over nite

If your getting fuel and white smoke warm up your engine and check glow plugs

 

[antfarmer2]

If your getting fuel and white smoke warm up your engine and check glow plugs

And part of the fuel rail can be fixed by you but Tazza will have to tell you

 

[Tazza]

And part of the fuel rail can be fixed by you but Tazza will have to tell you

I can't see the rqack being stuck again. The pump mounts to the top of the engine with the moving parts inside the engine cavity, it constantly gets oil spashed on it, there is no reason for it to stick again.
You can always check it i guess, remove the fuel shut off lever cover and see if the rack moves.