I have a bobcat 763 with approx 2500 hrs on it. I had a crack in the cylinder head and had it replaced about 6 months ago. Since then, whenever I'm backblading in reverse with a light load against the engine, the RPMs drop lower and lower to the point where I have to stop moving and let the engine regain RPMs so I can get working again. The engine can maintain normal power if i move the drive sticks a little bit but the tradeoff is that i move at a snails pace. When i try to work with some speed, the engine boggs down terribly and has lots of black smoke coming out the exhaust on top of that. Never had this problem before the head replacement. Ideas?
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antfarmer2
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Are you some how engauging your aux hydro while reversing?......put a gauge on you aux hydros.......it works fine in forward?
Yes. Forward works fine. Reverse is the issue. I can put the throttle up higher and it helps the problem but there is still bog with tons of black smoke coming out.Are you some how engauging your aux hydro while reversing?......put a gauge on you aux hydros.......it works fine in forward?
Aux hydrolics seem normal.Yes. Forward works fine. Reverse is the issue. I can put the throttle up higher and it helps the problem but there is still bog with tons of black smoke coming out.
antfarmer2
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Does it work fine forwordAux hydrolics seem normal.
antfarmer2
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Sorry just saw it did....,.can you put a gauge on the aux when reversing?Does it work fine forword
antfarmer2
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Maybe a stuck shuttle valveSorry just saw it did....,.can you put a gauge on the aux when reversing?
antfarmer2
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Any lights flashing or codes?Maybe a stuck shuttle valve
Its a '96. Doesnt have a code readout or any fancy bells and whistles lime the newer ones. We try to diagnose everything through feel during usage. Cant put a aux pressure tester on right now but arms and tilt work fine, forward works good, even with an engine load, but reverse with a load against the engine while trying to work with some speed is where the engine boggs to a point where i have to let off the drive sticks and let the engine recover. Not sure if the mechanic messed with anything else after replacing the cylinder head but there are no issues with any other systems.Any lights flashing or codes?
antfarmer2
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What happens if you back up and use the lift and tilt?Its a '96. Doesnt have a code readout or any fancy bells and whistles lime the newer ones. We try to diagnose everything through feel during usage. Cant put a aux pressure tester on right now but arms and tilt work fine, forward works good, even with an engine load, but reverse with a load against the engine while trying to work with some speed is where the engine boggs to a point where i have to let off the drive sticks and let the engine recover. Not sure if the mechanic messed with anything else after replacing the cylinder head but there are no issues with any other systems.
antfarmer2
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Drain the water seperator and change the fuel filterWhat happens if you back up and use the lift and tilt?
Boggs down real fast if i try to reverse while using arms and tilt. Never did that before.....Drain the water seperator and change the fuel filter
Wheres the water seperator ??Boggs down real fast if i try to reverse while using arms and tilt. Never did that before.....
antfarmer2
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Bottom of the fuel filter becareful mine is made from glass.........Wheres the water seperator ??
7LBSSMALLIE
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try to see if both sticks or just one. a bad relief replenish would be be the omly thing I can think of. but but the chances of two going bad, slim to noneBottom of the fuel filter becareful mine is made from glass.........
antfarmer2
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Im thinking your filter is full of water and getting worse and when you back up it is putting more water intry to see if both sticks or just one. a bad relief replenish would be be the omly thing I can think of. but but the chances of two going bad, slim to none
Ok. So i drained out the filter and alot of water came out; about a cup. Probably wouldnt hurt to replace it some day. Got about 6 inches of snow last night. The machine is running a little better now. I was going backwards with the sticks all the way back with a decent amount of throttle up and i worked the bucket and arms while reversing. The machine still boggs a little but it is not as bad as it used to be. I also might consider putting a quart of ATF in the fuel tank next time i fill up. Wierd thing today. I noticed during idle, the machine slowly rolls backwards now. At a dead crawl i'd say. Any idea how to adjust that?Im thinking your filter is full of water and getting worse and when you back up it is putting more water in
antfarmer2
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Good to hear now get a new filter........I did my 743 pain in the butt just get in there and see whats worn replace and ajust block all wheels off the ground I would wait for warmer weather if not that badOk. So i drained out the filter and alot of water came out; about a cup. Probably wouldnt hurt to replace it some day. Got about 6 inches of snow last night. The machine is running a little better now. I was going backwards with the sticks all the way back with a decent amount of throttle up and i worked the bucket and arms while reversing. The machine still boggs a little but it is not as bad as it used to be. I also might consider putting a quart of ATF in the fuel tank next time i fill up. Wierd thing today. I noticed during idle, the machine slowly rolls backwards now. At a dead crawl i'd say. Any idea how to adjust that?
I'm not convinced that the issue is the filter, the water needed draining, that's for sure.Good to hear now get a new filter........I did my 743 pain in the butt just get in there and see whats worn replace and ajust block all wheels off the ground I would wait for warmer weather if not that bad
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.
