20' Master Angler, Yamaha 115 four stroke

[Terry England]

Tom, you need to determine your "need for speed?". If you don't have a big Tee top with an electronics box and just a Bimini you will probably see 36 MPH with a 4000 rpm 24 MPH cruise with the 115. If you are trying to beat Donald Campbell's records you will need a lot more "juice". If you normally cruise at 20, don't run with a big load and don't want to spill you beer, you'll be OK with a 90. Just figure out what you are doing with the boat. They typically "push" pretty easy and were designed when the biggest outboards were Mark 78 Merc's.