Well cars have tank below carburetor. Why does mitsu car carb have shut off solenoid? Also it has a mechanical.fuel pump. Fuel going travel from.tank up to mechanical.fuel pump and up to carb? Photo is 1979 colt carb.
Thats your float needle not sealong against the seat and can happwn with any carbed engine. Yes diluted engine will eventually cause bearing failure but not the first time you run it.
Thats not the reason.Fuel in your oil isnt good but it wont kill your engine. My machine has tank below carb from factory Bobcat. Main reason is to stop pre ignition backfire.