I am beyond frustrated right now trying to get setup right on my 2017 Sweetwater Premium 255SB (2 25" tubes, no underskin or strakes). The boat has a new 150hp Mercury Four Stroke and I cannot get the motor into its recommended RPM range at WOT. Originally the motor had a 14.5 dia x 15 pitch Vengeance prop on it. Motor would just get into recommended range at 5100 RPM but at only 23 mph (GPS). That calculated to 31% slip. Whoa. Yesterday I tried on a 15 dia x 15 pitch Enertia prop. Boat felt way better but onmy reached 4500 RPM but at 25 mph (GPS). That is still 25% slip, which seems really high for an Enertia prop. Interestingly the motor is a 25" shaft on a 20" transom (it was ordered that way) because the dealer said that all of the SW Premiums were cavitating badly with the normal 20" motor, even in the bottom hole. So I am mounted in the top hole and the motor will only cavitate at the upper end of trim right before I hit the limiter. This seems right, but, if so, why so much slip. I can't see the cavitation plate when I look in the water because there is sooooo much turbulence (the motor cover is in a constant shower, literally water splashing all the way up to the top of the cover). The last part I can see before the water most is the neck of the lower unit where the access to the not for the anode plate is. There is still about 6 inches from there to the cavitation plate. I tried calling Godfrey, because I would think they would know about this issue as this is a very popular motor, but they were completely useless. They just told me to call the motor manufacturer. Really? They design the boat and have no idea how to set it up for arguably the most popular pontoon motor. Are you kidding. Coincidentally I tried calling
Mercury and they weren't of much more use as they don't know the boat. They just basically said that the Enertia line is the best prop for a pontoon. I am still amazed that Godfrey couldn't help. Has anyone run into this issue and how should I proceed? If there is a simple solution I would like to know it. If it is a design issue then I want to push Godfrey for an answer. HELP, please!