best guess on prop
 

I have read all the sticky notes on props, and I understand how all of it works. but, the issue I have is that I am at max rpm 4800 at like 3/4 throttle at 30mph. I have a high five 19 pitch on it now. would anyone recommend a 21 or 23 prop? I have no idea what the rpm's would be at full throttle because I don't want to open it up all the way and take a chance on blowing the motor. boat is a 92 mx19. any ideas would be appreciated

Re: best guess on prop
 

Normally a 19" 3 blade or a 20" 4 blade would be a much better prop for that engine. If your numbers are accurate then i would suggest something else is going on. Possibly someone has regeared the outdrive, your tach is not reading correctly or that "19" High Five (which is really a ski prop) isn't pitched as a 19".

Quick check for the tach is to access the back of the unit and spin the little wheel around 5-6 times then reset it at "6 Cyl".

I believe the outdrive gearing ratio for your motor should be 1.81 but i'm not absolutely positive. You can check what you have by using this chart.

Re: best guess on prop
 

i have only had this boat for about a month. the guy I got it from had put the prop on there. I don't really do any skiing, mainly just cruising around. I don't really like the prop because I hate the way it handles while I am in reverse. I will have to look to see what the gear ratio is when I get home.