440B Bobcat skid steer (Stalls under load)

[bird watcher]

Asking for some suggestions to repair 440B bobcat W/18hp Kohler engine that stalls under load. Engine will start and idle ok, but engine will start to stall when I try to drive off. If I nurse her ahead slowly she will move, but will hardly go up a small crest in the road. Things checked; fuel delivery, cut off selenoid activates, fuel line replaced, New Carb. new fuel filter. Does the same with or without air filter. new plugs. changed hydrostatic fluid. Can someone please give me some idea what may be causing the lost of power under load..

 

[RandyT]

First thing I would check would be the cylinder compression. I am getting to do an engine replacement on one in the next couple months. The current engine has a compression of 60 psi on both cylinders. It has like 2500 hours on it, so it is time for some work, if the guy decides to keep it.

 

[JJZ 109]

Probably would be better off to post in the Bobcat construction equipment forum and hope that SSDoxie replies.

 

[bird watcher]

Thanks for the reply: Any idea what the compression should be on this small engine. I know both cylinder should be about the same. I will do a search, but any help is appreciated.. (Excess black smoke coming from exhaust too).

 

[SSdoxie]

1. Does the 440B have auxiliary hydraulics?
2. When setting in neutral throttle up to full RPM.
3. Does engine run at 3000 RPM?
4. Will the lift arm go up and power as it should, and does the bucket dump and curl?

If answer to #2,3,&/or 4 is NO then check the auxilary lever, probably locked in detent. Move the Right Hand lever side to side to make sure it is in neutral.
Even if it does not have front auxiliary couplers, someone may have removed the lever lockout linkage and auxiliary spool got locke in detent.

FYI; compression should be minimum 90 psi with minimum 15% variance between cylinders.

 

[RandyT]

Thanks for the reply: Any idea what the compression should be on this small engine. I know both cylinder should be about the same. I will do a search, but any help is appreciated.. (Excess black smoke coming from exhaust too).

Black smoke means excessive fuel. It is trying to flood out. Low compression can also cause improper fuel burn.

 

[bird watcher]

RANDYT: Yes I will check the compression. I have a gauge and will let you know what I find. Thanks.
SSdoxie:
1. Does the 440B have auxiliary hydraulics? (NO)
2. When setting in neutral throttle up to full RPM.
3. Does engine run at 3000 RPM? YES. (Do not have a TAC- but I believe it does) really high rev in neutral.
4. Will the lift arm go up and power as it should. and does the bucket dump and curl? ( YES) & (YES)
Thanks for all the points;
When I installed the new Carb, I removed the governor arm had the governor arm in the wrong setting, when I corrected it, the bobcat worked like new again, lasted for about a day and then was back to the same fault of stalling under load. Could a bad governor cause this problem?. I incorrectly had it center of travel when it should have been maxed to one side..