Which prop?
 

Hello everyone!

I bought a Mariah 20/22SX (2007) two months ago. It has an Mercruiser 4.3 MPI engine and a stainless steel high five propellor. The top speed of this boat is about 82 km/h. Now I'm thinking to buy a new prop to get a higher top speed and to find out the differences between the props.

Does anyone have information about props for my boat. What about the pitch?

Thanks!

Re: Which prop?
 

What RPMs are you currently running? Also do you know what your current prop size and pitch is???

Re: Which prop?
 

See the sticky.... http://www.mariahownersclub.com/foru...ion-links.html

Re: Which prop?
 

If you are getting 82kph (50mph) out of that boat with the 4.3 you are doing very well.

Trying to achieve more top end will have it bog down badly out of the hole. I would suggest that you dont screw with it.

As DCB pointed out, check out the prop education sticky cuz a little bit of self education is always good. It's not rocket science but sometimes two similar boats with the same prop wont necessarily perform in the same manner so it can become a bit of trial & error at times.

As DougR pointed out, before you attempt to change anything you need to know what your RPM's are at WOT (wide open throttle) as the recommended range for your 4.3 is 4400 - 4800rpms at WOT. Going over the 4800 rpms causes extra wear on the engine & outdrive. Going below the 4400 rpms causes the engine to lug & work extra hard. Lowering the pitch usually lowers your top speed but improves your hole shot & mid range punch. Increasing the pitch usually does exactly the opposite. Generally a 2" change in pitch will result in a 400 rpm change. 3 blade props are generally the most efficient, 4 blade props tend to provide more 'grip' but cause some additional drag while the High 5 generally performs well but are expensive to purchase. Most members with the 4.3 run either a 19" 3 blade, a 20" 4 blade, a 21" 3blade or the High 5 prop in one of those pitches to keep it within the recommended range.

Re: Which prop?
 

Hey everyone!

Thanks for answering so far! At the moment I''m not able to find things out about the rpm's, because I'm living in Holland and the weather is realy bad over here!

More help is always welcome. I hope the weather is getting better soon so I can find out more!

Thanks!

Re: Which prop?
 

If you could "try before you buy" a couple of different props to compare overall performance you'll most likey stay with that HighFive. Also run with a GPS to verify your speeds. I'm also interested what pitch your HighFive is. Enjoy your testing and keep us posted with the results.

Dave

Re: Which prop?
 

If you switch from the highfive, you will likely achieve a minor amount maybe (1-2 mph) of top speed increase.... but your holeshot/pulling will suffer. If you are achieving those speeds with your current setup, I wouldn't mess with it.

Re: Which prop?
 

Thanks again everyone! I hope the wetter is getting better soon so I can find out more about my rpm's. Maybe I'll just try a 3 or 4 blade prop. I'm just curious... I'll post something about the "results"!

Thanks!