prop size for 1988 170 with 98 yamaha 90hp 2 stroke

[lasandoval129]

Anybody knows the right prop size for my 88 170 with a 1998 Yamaha 90hp 2 stroke? I want good top end...

[akbridge]

A 17" pitch should work well.  Try using factory Yamaha stuff.  They make good all around props.  Try to get your Rpms around 5200.  This will generally get you the best all around hole shot with good top speed.  You should see about 38 mph max with that setup.

[floridamisser52]

I've got a 1998 175 with a 9o hp cross flow . Got a 17 pitch factory original running 5200 wot rpm @ about  33mph with 2guys and 1/2 tank of fuel. Good hole shot, good performance through all ranges. That's how the factory designed the boat.

[wingtime]

I believe I have a 17" pitch prop on my 170's 1998 90hp looper. I get about 37 mph at 5300 wot.