Is it worth it a 743 and a 743b

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i just want to know your guys opinion on this. I have a chance to buy a bobcat 743 runs ok drives well everything seams to work well. It comes with a grapple bucket a tooth bucket and pallet forks. The secound bobcat is a 743b with a blown engine. This one comes with a grapple bucket and solid rubber tires (not really good condition). The motor over heated and there was water in the oil. I think the head may be warped i am not sure. The head is off but i cant tell if it warped. Well they want 5k for everything. Is this a deal worth going after? I am i going to have a huge nightmare fixing this 743b? I have had a 743 before and worked on it but i just dont want to be in over my head with this. Antother question what is the differnece of the 743 and 743b?
 

Tazza

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743 and 743B are essentially the same. As far as i'm aware there are only very minor differences like electric fuel shut down solenoid and the hydro oil filter is on the opposite side. The engine is exactly the same and i assume the pumps and motors are as well.
If the engine over heated warping of the head is the least of your problems. When these engines over heat the first thing they do is crack the head. This generally goes un-noticed straight away and coolant seeps into a cylinder and when you go to start it up you bend a con-rod that in the worst case punches through the block (i bought a machine like this).
Do your sums, a replacement engine will run you 3-5K. A bare cylinder head will run you around $1500 then you need a head gasket and you are not assured the bore isn't worn either. The bore may have distorted with the heat too. Unless you have access to a cheap GOOD engine you need to work out if you want to risk $1500 on a head for an engine that may need a full re-build.
If it was started or if they tried to start it, a con-rod may have been bent slightly. You can do a quick check by rotating the engine around to make sure all 4 pistons reach the same height. As the head is off this will be an easy check. Make sure there are no scratches in the bore and feel the top of the bore, if you can feel a ridge, not just carbon build up you know the bore is worn. This section of the bore is not touched by the rings and is a good indication of wear if you don't have a bore gauge.
If you do want to risk it on the 743B i have worked on a few and i have all the details for re-assembly and wear specs.
Good luck on your decision.
 

Tazza

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743 and 743B are essentially the same. As far as i'm aware there are only very minor differences like electric fuel shut down solenoid and the hydro oil filter is on the opposite side. The engine is exactly the same and i assume the pumps and motors are as well.
If the engine over heated warping of the head is the least of your problems. When these engines over heat the first thing they do is crack the head. This generally goes un-noticed straight away and coolant seeps into a cylinder and when you go to start it up you bend a con-rod that in the worst case punches through the block (i bought a machine like this).
Do your sums, a replacement engine will run you 3-5K. A bare cylinder head will run you around $1500 then you need a head gasket and you are not assured the bore isn't worn either. The bore may have distorted with the heat too. Unless you have access to a cheap GOOD engine you need to work out if you want to risk $1500 on a head for an engine that may need a full re-build.
If it was started or if they tried to start it, a con-rod may have been bent slightly. You can do a quick check by rotating the engine around to make sure all 4 pistons reach the same height. As the head is off this will be an easy check. Make sure there are no scratches in the bore and feel the top of the bore, if you can feel a ridge, not just carbon build up you know the bore is worn. This section of the bore is not touched by the rings and is a good indication of wear if you don't have a bore gauge.
If you do want to risk it on the 743B i have worked on a few and i have all the details for re-assembly and wear specs.
Good luck on your decision.
OOH one more difference is a 2 piece axle on the 743B, this makes changing axle seals easier.
 
Joined
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OOH one more difference is a 2 piece axle on the 743B, this makes changing axle seals easier.
Well with lots of thinking at night i bought the bobcats and all that went with them. I took a real close look at the head and i did not see any cracks. And the bores look fine and there is no hole in the side of the motor. Well this weekend i can take a closer look at all these things and see what i got. The other 743 runs well the only thing i can notice is that some times it bucks like a wild horse when i try to turn. O and is a little grey smoke is that normal when you start the engine? I cant remember does 10w40 go in the motor?
 

Tazza

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Well with lots of thinking at night i bought the bobcats and all that went with them. I took a real close look at the head and i did not see any cracks. And the bores look fine and there is no hole in the side of the motor. Well this weekend i can take a closer look at all these things and see what i got. The other 743 runs well the only thing i can notice is that some times it bucks like a wild horse when i try to turn. O and is a little grey smoke is that normal when you start the engine? I cant remember does 10w40 go in the motor?
I run 15W40 in the motor but it MUST be diesel grade not standard car engine oil. It needs the detergents to keep the engine clean.
Grey smoke? are you sure its not white'ish? if so, thats totally normal. Its just a bit of un-burnt fuel at startup.
I would get the head checked for cracks just to be sure, they mainly go between valves or to the pre-combustion chambers. If there are signs of pitting on the head its a sign of it using water.
When you are ready to re-install the head give me a yell if you need torques and valve clearance.
 
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I run 15W40 in the motor but it MUST be diesel grade not standard car engine oil. It needs the detergents to keep the engine clean.
Grey smoke? are you sure its not white'ish? if so, thats totally normal. Its just a bit of un-burnt fuel at startup.
I would get the head checked for cracks just to be sure, they mainly go between valves or to the pre-combustion chambers. If there are signs of pitting on the head its a sign of it using water.
When you are ready to re-install the head give me a yell if you need torques and valve clearance.
I will change the oil on the one that runs and it is a white ish smoke only on start up. I have to ask you Tazza how many bobcats have you owned? Another thing in your opinion what is the best skid steer bobcat has made? Thanks for all the advice
 

Tazza

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I will change the oil on the one that runs and it is a white ish smoke only on start up. I have to ask you Tazza how many bobcats have you owned? Another thing in your opinion what is the best skid steer bobcat has made? Thanks for all the advice
I have owned 5, but 4 of those were 743s and one was a 731. So i'm not really the person to ask about whats the best machine as i have only used 2 different models. If you want a machine just for around the yard you can't go past a 743. They are fully mechanical and any one with half a brain (like me) can work on it. I have no training in hydraulics or engines and i have fully striped a few machines down to repair them. From what i hear, the 743 was the best machine they ever built, they made the same machine for 10 years, i have never seen another model made for more than say 3 years.
If you want a machine to make money you really would be best buying a new machine.
 
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