Gunno

This is a new 90 horse Tohatsu. I'm pretty sure that the height is okay but would like it verified. I have a straight edge just under the cavitation plate. I've seen many others mounted a bit higher. Thanks. 

Thanks. Didnt even think of a one inch bump to 16. Probably not gonna be a cheap prop.

13 minutes ago, mr 580 said:

Seeing as you used selling dealer for high altitude setup, I think I would go back to them with your question for additional top end.  Could very well be you need a low level prop too.  Dealer should have an idea of how the motor ecu adjusts to the altitude difference.  Out East here on Great Lakes we don’t deal with high altitude setups.

Yeah... the dealer in my case are pretty useless I hate to say. I only bought if from them because they had the boat i wanted. The ECU is going to help advance ignition timing but it can't get more air (high altitude symptom) into the motor. The standard practice for mountain lake fishing is get a prop with decreased pitch prop (which usually come in 2 in increments). What I'm wondering is that maybe going to a 4 blade instead of increasing the 2 inches. Like I mentioned above I could read line the motor as is, so it's slightly underpropped even for high elevation. 

53 minutes ago, Bozeman Bob said:

Need your rated max RPMs for the motor. 

Max rates are 5300-6300 for this motor. I could over rev this motor if I wanted to so I know I need to increase pitch but I am wondering if keeping the current pitch but adding a 4th blade instead. I've gotta have decent holeshot for when I take it to sea level (outrun a swell coming aft of me)

So I got a new Thunder Jet 186 Rush boat with a 90hp Tohatsu (Honda really). Anyhoo, i had the dealer set me up with a high altitude prop (i usually fish at 4000 ft, sometimes higher, sometimes at seal level). So i definitely want to get some increased top end speed. Right now I get on plane instantly so dont mind losing a little of that. Okay, so my question is... go from my current 3 blade 13.5x15p to a 3 blade 17 or, and this is what I'm curious about... stay with 15p and switch to 4 blade. I'm thinking it may be a real sweet spot. Any suggestions appreciated.