My Champion 6.5HP Generator has a gas leak under the gas tank. The gas shut off valve is missing a rivet (one of two). I've got it unscrewed but am not sure how to get a replacement part. I have the owners manual and can find the part number, however, champion won't sell it direct and none of the visible print on this faded generator has a number that matches the model numbers on the Champion website. I can't tell what the model number is? The owners manual doesn't seem to tell me the model number, but I can find the part number. Nothing pops up when I try searching the internet with that and my searches for buying champion generator parts lead in circles, redirected to one list after another of discount sites but not that allow me to order the part from the part number.

The floater of the carburator is bad(Needle). its leaking gas at the carburator and the gas is coming inside the engine at piston intake valves.
Replace carburator needle that stops the intake of gas at the Carburator.

The unit could have trash in the valve not allowing it to seat. Relief air and clean. If the unit blows air out for a couple of seconds after the unit shuts down that is normal. That is how the pneumatic valve works.

I guess you mean it leaks air from underneath the On/Off switch?

If that's correct, it sounds like the check valve is leaking. On the tank there should be a pipe that goes under that switch. At the tank end of that pipe, there is a check valve. Before you unscrew it MAKE SURE THERE IS NO PRESSURE IN THE TANK!!! You should be able to unscrew it, the check valve consists of a light spring and a plastic or rubber stopper looking thing, have a look at it, if possible clean it or replace it. Put it back together again, and try it now

The code is for a large leak in the EVAP system such as a loose or missing gas cap. But it could also mean a loose or missing hose to the canister or other leak in the tank.
The computer vents the tank several times an hour while the engine is running, and it checks the system by pressurizing the gas tank. If the tank will not hold pressure the code is set.
You may have to check the top of the tank where the fuel pump gasket is, as well as the vent lines to the front of the car.
A mechanic would perform a smoke test to look for leaks.

Make sure that fuel flows freely from the tank to the carburetor. There should be a petcock (shut off valve) that has a screen on it (inside the tank), which also can become plugged with sediment. Work backwards from the carb, checking also the fuel supply line, back to the tank.

--W/D--

sounds like it..take a pencil and open it and see if it shuts off

Simple fix- Close fuel valve disconnect the fuel line below the shut off valve then open fuel valve and drain fuel out of tank into a safe device that will hold the amount that's in the tank. When done draining close valve reconnect fuel line and refill tank with fresh fuel. The oil in the gas won't hurt your engine it could fowl your spark plug if so just remove clean and re-gap.

possible problems not knowing age of unit the
control valve could be sticking open allowing gas to continue to flow until high limit is reached and shuts down valve another possible problem with the newer style back flow preventer being install by water companys the rapid heating and expansion of the water over pressures the water system causing releif valve to pop open and reclose most water heater manufacters are recommending instalation of an expansion tank to allow the growth in volume of water somewhere to go is valve constantly leaking or only during heating cycle if you could supply additional information does unit only leak when heating
or is steam expelled when releif valve opens
t-stat not opening gas valve sticking partially open
bad high limit bad pressure releif valve no expansion tank to allow for thermal expansion if steam is present and unit is boiling water inside replacement of water heater for safety concerns,would be reccomended if only water and pops couple of times water temp not over 140 degrees after most hot water has been used out of tank and is reheating most of capacity probably lack of expansion tank as the releif valve is the final safety device on a water heater is of great concern
the temp control gas valve or high limit are supposed to shut unit done long before the safety limit of releif valve is reached

explore the possibility of removing & replacing the 'petcock'[fuel valve] in the tank.drain tank,remove gas line,unscrew petcock retaining nut at tank & replace.