Two things might be happening here:
1. The 7745 did more than you payed for
2. or the 7341 does less than you payd for.
If the 7341 does less than you payd for, i think it is reasonable to ask the dealer to correct the power to manufacturer's setting, because that's what you payd for.
It is also possible that the 7341 has never worked yet, and needs to "burn loose" to burn out all the sludge and carbon out of the cylinder head.
Over here, when we use the 5245 with a 5800 liter ( 1526 gallon ??) tank, it can hardly pull it in the spring, because of the carbon build up during the winter, when it does only a few light yard tasks. After 5 to 10 tankers, the engine is burned clean, and it pulls a lot easier.
About the newer
fuel pumps, i have no idea how to set them. On the old pumps, like the 6718 there is a screw behind an oval cap on the regulator housing, but for the new pumps as used on the 5245, i havent figured it out yet.