My 18 foot boat with 4.3 mercruiser has a 4 blade 19 pitch prop it easily runs up past redline 5000 with lots of throttle left should i change to a 21 or 23 pitch
Its hard to actually see if the boat is coming up to high. Another boat running along side could get an idea. If the prop gets close to the surface it will start to get air in and will ventilate.
If it does ventilate the rpms increase but speed does not
Surely an IO should not ventilate when running level?
Maybe in tight turns yes but its not the same as an outboard which might be set up too high on the transom?
