Carburetor

First of all, if this was the incorrect carburetor, you would have always had problems. The engine would not have ever run properly. What you need to do is get the engine to stall, then do not try to restart it. You want the problem to be "findable". Remove the air filter cover, then work the throttle by hand and watch if gas is squirting. If this is a two-barrel carburetor, you might have to hold the choke blade open to see the gas spray. If it's a four-barrel, the gas will spray from the two front barrels.

If there is no gas spraying in or the streams are very weak, the float bowl is empty. The best suspect is a collapsed strainer sock inside the gas tank. They will stretch out after sitting for a few minutes and allow gas to flow through it again. At that point you'll need to crank the engine long enough to refill the float bowl. Typically that only takes ten to fifteen seconds.