763 engine boggs down while reversing

[Bobcatdan]

I'm not convinced that the issue is the filter, the water needed draining, that's for sure.
Only bogging down in one direction is very strange.... A stuck valve would just give a lack of drive power, not bog the engine down like that.
Black smoke is too much fuel, not enough air. That can be due to excessive load or a restricked air filter, so check the air filter too.

I would jack the machine up and run it. Does the it do the same thing? Something is going on with one or both drive motors causing excessive load on the engine. There is nothing wrong with the engine as far as I'm concerned. The engined doesn't know which way you are traveling, it merely reacts to load. If it is pulling down that bad only when backing up, that points to a drive issuse.

 

[bobcatguy]

I just operated a S175 with roughly the same problem. This machine bog down but only while performing 2 other functions while in reverse. If you'd lower the boom and curl the bucket while going in reverse the engine rpm would drop significantly. The owner brought the machine to a dealer who changed the drive belt (I'm not sure why) which didn't fix the problem. I'm going to be operating the machine some more in the near future and will do some checks to see what I can figure out.

 

[biggie]

I just operated a S175 with roughly the same problem. This machine bog down but only while performing 2 other functions while in reverse. If you'd lower the boom and curl the bucket while going in reverse the engine rpm would drop significantly. The owner brought the machine to a dealer who changed the drive belt (I'm not sure why) which didn't fix the problem. I'm going to be operating the machine some more in the near future and will do some checks to see what I can figure out.

REALY?????????

 

[theonlyrussell]

I just operated a S175 with roughly the same problem. This machine bog down but only while performing 2 other functions while in reverse. If you'd lower the boom and curl the bucket while going in reverse the engine rpm would drop significantly. The owner brought the machine to a dealer who changed the drive belt (I'm not sure why) which didn't fix the problem. I'm going to be operating the machine some more in the near future and will do some checks to see what I can figure out.

Did you ever get it figured out? I have my skid steer doing the same thing after changing the cylinder head. I have narrowed it down to being a faulty cylinder head. I had just bought an aftermarket one from Kumar bros and found the prechamber ports not cut correctly. I think it doesn't atomize the fuel correctly. Mine is also hard starting when cold.

 

[Tazza]

Did you ever get it figured out? I have my skid steer doing the same thing after changing the cylinder head. I have narrowed it down to being a faulty cylinder head. I had just bought an aftermarket one from Kumar bros and found the prechamber ports not cut correctly. I think it doesn't atomize the fuel correctly. Mine is also hard starting when cold.

For the starting, i'd do a compression check first.
The pre-combustion chamber is just a pocket for the flame to start expanding, the injector is to atomize the fuel for ignition.
Do you have any pics of how the chambers were not cut correctly? I wonder if they were not aligned correctly, if that could be caussing issues. I know the opening was made to face inwards, but i don't remember if they are meant to face a specific way to allow the flame from the injector out the hole.