300/440/550 550 has no throttle response

[kzkilo]

It is also backfiring through the carb. It has a sbn 44 on it with a stock head and stock pipe. It runs great out of the water but once you put it in the water it doesn't have any throttle and will pickup once in awhile then bog down again. Not sure what the adjustment screws are at or what pop off spring is in it

 

[restosud]

check you stator,flywheel and compression.known for front crank snout and seal damage if any amount of hours on it.