Re: Pontoon travel speed?
Ok well it may be well right on RPM`s if it is way over propped. A prop is matched to the load and the motors max PRM.more info on youir motor is needed to find what it should be turning but a very general RPM range is around 5000 to 6000, it may well be more or less. The bogging down your describing could be a motor problem or it may be way to much prop pitch and that's all it can do. Common pitch numbers 9,11,13,15 for a pontoon, my guess on a 60 on a 20 for pontoon is a 11 or a 13. Take a look at your prop and take pictures of any markings, and you may have to take it off, some times its molded in a blade or on the hub its self. Lets start with that.
I will explain a bit more about props. A prop is what limits your RPM and keeps your motor from over revving.
To much pitch and it wont make it up to the WOT rpm speed and wont make its rated HP. To low of a pitch and the motor over revs and will blow up.
So matching a prop to the load its pushing is very important. So finding out what prop you have will give a indication. And also the exact motor , type 2 or 4 stroke, and year will also help. that will give you the RPM, it should be marked on the motor its self.