Step-dad's husky is running rough

[jcims]

Hi folks,

I don't have much information to provide at this point, just looking for tips and/or things to look for. Step-dad has a 2000 vintage Husky hydrostatic riding lawn mower...probably 48" deck. Pretty light machine, I would imagine one of the smaller models of that era. It has a Kohler engine (not sure if they all do).

It's run flawlessly until this season. He's now having trouble keeping it running for more than an hour. I'm just going to convey a few of the symptoms he's relayed.

* Starts fine. Runs fine until it's hot.
* After an hour or so of cutting on flat areas, begins to run 'rough'. RPMs drop and the engine lugs and chugs. Throttle increase will momentarily smooth operation and it will resume lugging/chugging.
* Seems to happen more quickly if he's on some type of incline.
* Continues until he stops the engine and allows it to cool.

He's flushed the gas tank, changed the fuel filter, no improvement. He said the manual said 'check the oil', and it was a bit low. He added oil and it seemed to improve the situation. I'm heading over tomorrow to take a look. I have husky saw, trimmer and push mower, but don't know anything about their riders. He said there's a little 'box' on the side of the crank case that the fuel line goes through. Any ideas what that is? Is it related to the oil level situation?

 

[honorbound]

Does the fuel line hook up to the box? Sounds like it is a fuel pump that the line is hooked up too. The spark plug could be starting to go bad so replace that first to see if that helps. Make sure the top of the engine is clean of any grass or dust build up to try to prevent overheating as they are air cooled engines and the flywheel does the cooling by blowing the air over the engine. Start there and let us know how you make out.

 

[jcims]

Does the fuel line hook up to the box? Sounds like it is a fuel pump that the line is hooked up too. The spark plug could be starting to go bad so replace that first to see if that helps. Make sure the top of the engine is clean of any grass or dust build up to try to prevent overheating as they are air cooled engines and the flywheel does the cooling by blowing the air over the engine. Start there and let us know how you make out.

Thanks for the suggestions honorbound. I looked at it this weekend and the 'box' has a diaphragm membrane in the center and a hard line from the output side to the carb, so i'm nearly positive it's a pump. He just replaced the fuel filter and spark plug and is going to give it another go this weekend. I'd seen someone also mention that the vent on the gas cap can become clogged, impeding fuel flow. So he's going to try a few things, and if it doesn't work, we may rebuild the pump and carb and put a new coil on it.

Other than that, it's still very sound mechanically for a relatively inexpensive rider.