In the old days moth balls were at least in part if not all made from naphthalene. They either raise the octane or make the fuel run hoter, not certain. I remember it being one of the grab bag of tricks used by some racers at least on the local short track and drag strips. I never tried it for fear of doing damage. These days most moth balls use something else so don't just go buy a couple of bags and expect improvement. Around 20 years ago some shady fuel delivery folks were using a no longer used gravel pit to haul in tanker loads of the liquid form of naphthalene to mix with fuel they had just picked up from the fuel distribution center. They were mixing in whatever their ratio formula was to cheap regular and then delivering it as premium. True story. They had bought a Honda water pump from the shop I worked for at the time. They lost both tankers when a spark set it all off in an explosion heard across north town. The "mixer" recieved painful but survivable burns. The next day the fire dept. was in the shop to see if the Honda water pumps were properly labeled not to be used for flamable liquids. They were and are of course, along with warnings in the owners manual. The fire dept got what they wanted, additional charges against the illegal fuel operaton for using un-approved pumps to tranfer the fuel.

The carb looked pretty good when I had it apart. The fuel flow at the lines was poor and the valve grommet was damaged. I did assume a blockage, so I just replaced all the fuel lines and valve/grommet. I also checked inside the tank when I had it emptied and it looked good...also looked around from the underside when the valve was out and it looked clear as well. But to be honest, since then, I don't recall checking the flow from the valve so I'll do that.

Yep, last year my tractor did the same thing! And, i checked all of those things, and finally did the trick with the thin wire in the gas cap! Some years ago, a man made me a gift of his aging Wheel Horse tractor. Said it had those same problems. I tried it out, and sure enough, i hadn't run it more than 3-4 minutes, and it stopped running. Of course, i opened the gas tank cap, and made sure it had plenty of gas, at least enough to run. Started it up again, and in 2-3 minutes--bingo--it quit. Removed gas cap, looked in, plenty of gas, put cap back on, ran for 2-3 minutes and--same thing! And then, it dawned on me--open the hole in the gas cap! I did, and problem fixed! I opened the hole in the gas cap, and it was fixed! I offered to give it back, but he said to keep it.

Hi Joe. Many times the correct answer IS leave it to a pro, not always, but more often than not. Now you are correct, it does not answer the OP's question. My answer served to start this post moving, and provided sound reasoning why it's not prudent to answer his question. Answering his question could give him enough information that he might attempt this dangerous repair. The qualifier, of whether he thinks he is capable or not might sound good from your position at the moment. Being the person that possesses the information he seeks (among others) and my not knowing if he is sufficiently skilled, and equipped to attempt to do this safely it would be irresponsible for me to explain this routine. JMHO. I would not give this repair to a technician that has less than four years experience. Even then he/she would be directly supervised and personally instructed in the steps required to perform this repair in a safe manner. There is no drain for the fuel tank. There is no access through the floor, the tank must be lowered from the vehicle. The fuel is removed with specific equipment and considerable care to allow the fuel to be stored with no loss of liquid, and very little vapor leakage. There is a special adapter that fastens to the shops transmission jack, which allows fuel tanks to be strapped securely to the jack to prevent slipping and tipping. One common mistake people make is the kind of lighting they use to allow them to see while servicing a fuel system. Drop lights, that use incandescent bulbs are the most common ignition source when a fuel spill occurs. First you have a fuel spill which sets the table with a sufficient load of fuel vapors, and then true to it's name the light drops and the bulb breaks which allows the hot filament to ignite the fuel vapors in a violent explosion. This has resulted in loss of life, serious injuries, and extensive damages to businesses garages, and homes. If you want to enable the O.P. to place himself at risk of a catastrophe, for the sake of a few hundred bucks, then go right ahead.