I have a CountryClipper Zero-turning radius mower with a Kawasaki 23 hp engine FH680V. I have had it a little over 2 years and it has less than 100 hours, which for a commercial grade mower isn't much. When it is running right, it cuts and spits out the thick grass like it was nothing! The engine rumbles like a race car. It has great power and compression. But this season there is a problem. When I engage the mowing blades, the engine starts to cough and sputter like it will die. I turn off the blades, the engine recovers, I turn on the blades, it sputters. After a few minutes of this, the engine recovers and runs normally for 5 or so minutes and starts this sputtering again. And if it is mowing and cruising in light grass, it will start to choke if I plow into some thick grass. Like a sudden increase in load on the engine causes it to choke up. I discovered oil inside the air filter and some down in the carburetor. I cleaned up what I could, replaced the air filter, cleaned the spark plugs (which were not oil-fouled as I though they would be), sprayed carburetor cleaner down the choke. It runs better for a little longer after I clean it, but it still will get into the choke/cough/die routeine after about 15 minutes instead of immediately when the blades are first engaged. This oil in the carb thing is not one time; it continues to occur with use of the mower. I added fuel additive to the gas several times. The gas filter has gas in it that you can see through the plastic. I called the dealer and he said, "Take off the carburetor and bring it in, but just watch out because there's a lot of things you could mess up." (I thought, "That's a lot of help!") Does anyone have a suggestion for something to try before I attack the carburetor and risk "messing something up?"

Another question: Can I use NGK BPR5ES sparkplugs in place of NGK BPR4ES?

I am not a pro, but I know an engine can run on one cylinder and you'd never know it until you apply a load, then it runs poorly. I just had a similar problem with a briggs 18 horse. I rebuilt the carb 3 times, changed head gaskets, manifold gaskets, even tried a dfferent carb, new plugs, new fuel line, etc. Finally I tried the coil and sure enough, that was it.

I hadn't thought of the coil, but that is something I could check myself. Thanks a lot for the suggestion! My thinking was stuck on a fuel supply problem. I appreciate it.

This is just FYI from my experience with this mower problem, because I was incredulous this could actually be the reason.

I had changed the oil and used 100% synthetic generic "house brand" distributed by the 'world's largest retailer." I figured that 100% synthetic must be good, right? And surely 100% synthetic, even that distributed by the "big W," would be better than name brand oil.

My son had also used this same house brand synthetic in his Honda Oddessy and said in a short time it was running rough with less power. He changed the oil to a name brand synthetic and said the car ran fine. Obviously, he was not thinking too highly of this house brand synthetic. He said the heat from my Kawasaki air-cooled engine must have broken down the oil so it was being thrown into the carb and fouling it up. But, my lawntractor ran so badly, I couldn't believe the answer could be that simple. To help convince me, he came over and we changed the changed the oil to Pennzoil 100% synthetic.

I am both amazed and glad that this lawnmower had run great since, just like it ran before all this problem developed. And I learned a few things about supply sources to avoid for oil and synthetic.

For what it's worth.

Different heat range plug, I would stick with the BPR4ES.

ive said this before and ill say it again kawi's love to throw pushrods and bend pushrods just a thought good luck

'30yearTech' and 'big ed'

Thank you for replying. I appreciate the information.