I have the Ultra with the B-S engine. The problem I have is that when you take on a short steep incline or a bumpy terrain it coughs and sputters like it is fuel-starved. This makes for a crappy ride and who knows what it does to application rates. It does it if the fuel tank is full or near empty so I eliminated a fuel tank problem. Maybe sloshing in the carb bowl? Do any of you have this problem? I know there are some here who have nothing good to say about the PG but I'm looking for a solution. Oh and I did have a break down last week.The pump died. PG overnighted a new one to me at no cost. It seems the pumps have an internal wiring problem. More of Sureflo's problem than PGs.