My 8x8 Argo Conquest with the 20hp Kawasaki FD620D engine hasn't been used for a couple years so I rebuilt the carb and flushed the old fuel out of the lines. After putting it back together I noticed the fuel pump never shuts off and I'm assuming it's flooding the carb/engine because the engine will only start up and run for about 1-2 seconds before it dies. I know the carb is getting plenty of fuel as it pours out of the drain plug when opened. It's an aftermarket fuel pump, however it's worked fine in the past. I put a new float valve in the carb and the float appeared to be fine as well. Any ideas on what I should look at?