Hi all, I've got a 2003 48" Exmark Turf Tracer HP with the FH500V 17HP V-Twin Kawasaki engine. I bought it used last spring, and as long as the choke is almost completely closed it runs perfect. No smoke or missing. I used it all last season this way, and it performed just fine, but now that it's winter, I'd like to get it operating correctly. When I open the choke all the way to normal running mode it leans out and acts like it's run out of gas and dies. When the choke is completely closed it does start right up every time first or second pull (recoil start), even in the cold. And if you leave it on too long, it will run too rich. So the choke works, just for some reason when opening it, you can only open it so far before it runs too lean. It's supposed to run normal with the choke all the way open, but it doesn't. I don't have many ideas as to what might be wrong. Maybe a clogged jet? Bad fuel pump? The fuel filter and air filter are new and good. Spark plugs are new. Like I said it runs perfectly when the choke is in this certain position. Any ideas? I greatly appreciate your help.