exmark metro, fh451v-bs04, the mower always ran good, but had sat for over a year. The engine surges at idle and will only smooth our with the choke about 90% closed, if you close the choke all the way it dies, open it back up just a little and it runs "smooth" but still not right. opening the choke any more than that cause the idle to surge up and down. I took the carb off the first day and it was all gummed up and of course the "old gas" smell was horrible. I drained the fuel out of the tank and lines and pump. i completely dissembled the carb and let it soak in a gal. of carb cleaner overnight, put it all back together and still did it. Took the carb off 2-3 more times cleaning it each time. The plugs are good and have good spark, checked compression, adjusted valves, sprayed carb cleaner around intake and carb gaskets to rule out gasket leak. and even though i don't like messing with governors i readjusted it too. even though it didn't need it and didn't change anything. The last thing i did to the carb was an old carb cleaning trick that i picked up from a farm equipment web forum and that was to boil the carb in gal. of water with a 1/2 cup of tide detergent for an hour. still nothing. i've clean, sprayed with cleaner and blown out with compressed so many times i'm sick of it. The only thing left is the needle valve. it "appears" to be in good shape and i think it is doing its job properly. I hate to replace it cause the cheapest one i've found is 15 bucks and have to wait on shipping and i dont think that is the problem. Last but not least, all of the little brass plugs that are pressed into some of the holes in the carb seem to be in place. I'm at my witts end and dont know what else to do. There is a john deere dealership close to me that has an ultrasonic cleaner they said they could put the carb in for $15 but I dont know if that is going to help or not either. Adjusting the pilot air screw with the engine running makes no difference. Can anybody come up with anything else i can try or offer any suggestions. And if push come to shove and i have to order a needle valve. Where is the cheapest/fastest place to get one?