Prop and Engine Performance

[THEFERMANATOR]

http://www.propgods.com/content/propellers.aspx

This will give you a basic idea of what MERCURY's props do. Check your engine height first, and if that is good see if you can find a 15 pitch ENERTIA. You may actually need a 17 pitch with it though, and remember that every prop will have a different engine heght it likes. Some like to run high and cavitate a little, and others have to be buried in deep all the time. I would think with the bracket though you would want a sternlifter as bow lift would be a problem on a sloppy day.

When checking your engine height you will need 2 people. One person drives and the other goes back and looks at the engine. You want to be able to see the caviatation plate just a little bit as a good starting point and go from there.
Like this

[joe7670]

OK, you guy are too far from here. I would need someone that knows how to run the boat and trim it or freakining take a pic. of the cavitation plate.

The numbers specified are with me running the boat and trimming to what I think is adequate.

The videos taken are with my cousin trying to run the boat... has no clue on triming or much of anything. Can't even run the camera right while i'm running the boat.

I am curious to see the cavitation plate while underway but can't manage to do that properly while driving. lol

I can tell you one thing, the motor is about 3/4" high based on the requirements for motor height with set back.

Sound like it may take one more trip to get the answers I need?

On the trimming, it's not as easy to notice proper trimming with hydraulic stearing. On teleflex it seamed easier to me.

[THEFERMANATOR]

If you still have the engine hook just raise it up one more hole and try it. You'll know right away if it's too high as it will try and blow out coming on plane, or you will hear a buzzing sound when you trim it. When trimming for your top speed run, you want it trimmed to the point that the bow feels like it's airborne and almost jumpy. When I get em trimmed out high for top end runs and feels like it's trying to take off on every wave. your numbers still aren't bad for that boat and engine combo as it sits, and the MIRAGE will give you goo cruise numbers offshore. It isn't a top speed prop though from what I have found, it actually seems to work better on heavy tanks. I put one on a SEARYA 250 cuddy cabin and it made that boat fly compared to a regular stainless prop.

[RidgeRunner]

Joe, I had a 200 merc carb on the 20 cc for a while. It would turn a small diameter Quicksilver 17p past redline to 6100 and when I put the 17p Mirage it brought the rpm back to 5800. If you were not heavy when testing with the 15p sounds like a smaller pitch or diameter may help. IMO Prop testing should be done at high speed, trimmed out all the way. If you get to the redline with a light load it should be pretty close to perfect. I am pretty sure they build in some break in time in the computer on the Opti, you won't know what you have until you get past break-in. But I am not sure how many hours that takes or what the computer is doing during this time (I expect it isn't seeing max timing at WOT)
How does the boat sit in the water with the bracket?
I misread the first post. It should definitely turn the 15p

[joe7670]

Actually, it's very possible that the electronics limit something cause there is a "Break in" period of 120 minutes on the guages. I'm down to 60 minutes or so.

I added a picture of how the boat sits below. It sits a little lower that it used to in the back. Not that I ever had it in the water but just basing on the prior water line. I'm talking maybe 1/2" lower, nothing crazy.

Sounds like i'm going to have to go out on one more trip to get out of break in mode, get better pics and maybe take a friend that knows how to drive or take pics. After that trip I may have more info.

[RidgeRunner]

Sweet, that picture says it all. I knew it would work. My cc sits much lower in the stern. I think about up to the top of your stripe.
I agree that motor height needs to be checked. You will get it figured out it just takes time. I have a smaller diameter 19p Quicksilver if you want to try it.

[joe7670]

Thank you for the offer, but the shop is willing to work with me on the props. which is pretty cool. I am waiting for them to get in to bounce the #'s off of them to see what they think as well.