Bobcat s185 bogs down when using hydrolics

[Bill Jones]

I have a bobcat s185 turbo, and it has some bogging down issues. The bucket can move up and out with no problems, but as soon as i move the bucket down and in (at the same time), the bobcat bogs down and nearly stalls. It also bogs down with fast acceleration or top speed. It especially doest like it when combining these 3 functions (bucket down, in, and full movement). When doing all 3 at once, the belt will slip and sqeak.

I just replaced the hydrolic/hydrostatic fluid and filter (messy job) and it seems to have helped but only a little. Someone suggested it could be a fuel filter, and that was replaced about 100 hours ago but this machine only gets used for about 30 hours a year.

Any help or ideas would be greatly appreciated, thanks

I'm really hoping its not something big like a hydrolic pump. Someone else also suggested that it could be that the belt isn't tight enough on that pulley.

 

[tractormech]

Fuel filters are cheap. Change them so you know they are in good shape. Hours are low but time has passed and algae could be present and clog filters in a hurry. Will it rev right back up when it bogs if you release all load?. What engine is in it and will it run at high idle sitting still without bogging down or sounding like it's starving for fuel?

 

[willie59]

You need to clarify "bog down". Does that mean the engine loses RPM, or does that mean the engine holds its RPM but machine functions slow down? I ask this because you mention that under hard load you can hear "the belt slip and squeak". I assume you mean the drive belt. One thing for certain on a Bobcat, if things are proper, no matter what the load is you should never hear the drive belt squeak. If you do, that's a problem.

 

[Bill Jones]

Dont know exactly what engine but its a Kubota inline 4 turbo diesel. The bobcat is an s185 and is approximately 15 years old. I will order a new fuel filter. By bog down I mean it looses rpm like its going to stall. When I stop moving, it revs right back up. It will maintain a high rpm without moving, and can raise and tilt out the bucket while maintaining wide open throttle. Its only when lowering and tilting in the bucket that it looses rpm. And when driving quickly. Im not familiar with belts. I would assume its the drive belt slipping. Ive noticed that while its "bogging down" the belt will sometimes squeal and if its at idle and i quickly rev it up to wide open, the belt will occasionally squeal. I know that the drive belt was changed last year.

Thanks for the help so far

 

[Bill Jones]

I forgot to mention that when the machine is at or lower than mid throttle, there is no problems at all even under load. It is only at high to wide open throttle that it has these problems under load

 

[willie59]

If your engine is losing rpm under load it's a fuel related issue, could be a number of things, but one common problem with Bobcat machines doing this is something blocking the inlet of the pick up tube inside the tank. Bobcat used two styles of pick up tube, one was a flexible tube with a strainer screen on the end, the other is a more rigid tube with no strainer. It sounds like your machine is in the first stage of fuel delivery problem, very intermittent, only happens under hard load. With pick up tube blockage its easier to diagnose when it's so bad it stalls the engine, when that happens it sucks the primer bulb in the fuel line flat, sure sign the pick up tube is clogged. But in your case, it could be a hole in the supply line sucking air, could be lift pump, any number of things, not enough info for me to say for certain. As for the belt squeal, check all your belts including the drive belt. You should not hear a belt squeal on that machine if things are proper.

 

[Bill Jones]

If your engine is losing rpm under load it's a fuel related issue, could be a number of things, but one common problem with Bobcat machines doing this is something blocking the inlet of the pick up tube inside the tank. Bobcat used two styles of pick up tube, one was a flexible tube with a strainer screen on the end, the other is a more rigid tube with no strainer. It sounds like your machine is in the first stage of fuel delivery problem, very intermittent, only happens under hard load. With pick up tube blockage its easier to diagnose when it's so bad it stalls the engine, when that happens it sucks the primer bulb in the fuel line flat, sure sign the pick up tube is clogged. But in your case, it could be a hole in the supply line sucking air, could be lift pump, any number of things, not enough info for me to say for certain. As for the belt squeal, check all your belts including the drive belt. You should not hear a belt squeal on that machine if things are proper.

Great, ill let you know how it goes. The bobcat has done a lot of sitting, so algea in the tank is possible. Since the drive belt was replaced, its very possible that it wasn't tensioned properly. The previous owner said it used to starve for fuel when throttled up and that it was fixed when he replaced the filter, but that was 3 or more years ago. Ill also let it stall and check the primer. Thanks

 

[tractormech]

Willie is telling you right-those lines can get stopped up and run you crazy. I might put some algaecide in the tank. I've seen tons of Bobcat stuff with an inline filter installed before the fuel transfer pump and regular filter. You can get a piece of hose and a clean bucket of fuel and tie it off and run it and see if the issue goes away. Also, see if it's a 2203 Kubota with the little lift pump an the side of the pump block and let me know. Try the fuel bucket and inline filter first. Interested if it starts running well at full throttle or it acts the same.

 

[Bill Jones]

I had someone watch the primer bulb while I bogged it down, the bulb did not collapse. It is a kubota model V2003. Havent had a chance to run it from a bucket yet. Should i check the old fuel filter to see if theres build up in it or should i wait until I get the new one?

 

[Bill Jones]

Update: I tried taking out the air filter and the problem almost completely went away. It still drops rpm a little but it never comes close to bogging down and the belt never slips. I put it back and the problem returned. Im thinking that a new air filter along with a new fuel filter and maybe some general tuning and adjusting will have this thing running like brand new. Thanks guys for all your help, and any more advice/wisdom is still appreciated

 

[tractormech]

I'd replace fuel and air filters and see if it runs. If the air filter is in that bad of shape the others aren't much better. Change them all so you have a fresh starting point.

 

[Bill Jones]

Already ordered them. Thank you

 

[willie59]

Was the air filter clogged with dirt or diesel soot? If you get a hole in the exhaust system on a Bobcat it will clog that filter with diesel soot.

 

[Bill Jones]

It seemed pretty clogged up, and sure enough there is a large hole in the exhaust. At one point the tail pipe was backed into something, which caused it to start to crack off of the muffler. I used lacquer thinner to wipe the soot off of the inside of the door, turning it from black into orange again.

 

[barnbuilder]

Maybe pull fuel line from primer bulb and blow though the fuel line. Mine has something in the tank and I have to do this every couple days. Its free and easy.

 

[Bill Jones]

Blow into the tank or the other way?

 

[willie59]

You have to know which pick up tube you have before you do that. If it's the rigid poly tube, blowing air back through the fuel supply line from tank is no issue, just be sure to remove the fuel cap first. But if you have the flexible tube, DO NOT DO THAT, you'll either blow the tube off of the elbow inside the tank or you'll blow the strainer screen off of the end of the flexible tube.

 

[willie59]

If you have an exhaust leak inside a Bobcat engine compartment it "will" clog the air filter and cause engine running issues. You need to fix that for sure.

 

[barnbuilder]

Blow back into the tank. I just use my mouth. Usually out in the middle of no where. I've had to do it for years. I tried draining the tank with no luck.

 

[Bill Jones]

I'll probably end up welding the exhaust back together. I hate to say it but I have no idea which type of fuel system I have.