Changing prop!
 

Hi!

I'm thinking about changing the propeller on my Mariah SX19 '06 with the 4,3L MPI engine and the Alpha I drive. I'm looking for overall good performance, and some more MPG would be nice. With the fuel prizes here in Norway the propeller could be pretty expensive if it gives me a few % fuel savings:p Every internetpage and magazine I have checked out say much good about the stainless steel propellers. I also checked out Mercurys "Prop Selector" (link below) and found out that they also make positive comments about their stainless steel props. The props that I found most interesting were the Revolution 4 and Laser II. Anyone here who have tried changing propeller? Alu vs. Stainless steel? Positive/Negative things?

Lars

https://appcenter.mercurymarine.com/...lector/home.do

This will be a great question for MikeyT to answer, he is our resident prop dude. There are many threads here talking about props so do a search on it - http://www.mariahownersclub.com/forum/search.php - and you may just find the answers you are looking for.
Occasionally props will come up for sale on this site and other sites also including eBay, so that may also be an option if you want to keep the expenses down.
There as SO many variables with prop selection, in the end it comes down to your personal requirements - speed over fuel consumption etc etc.
Let us know how you get on when you're done.

Thanks for the info! I'll do some research ;)

definitely go with a stainless. Depending on your altitude you will probably want a 20 or 19 pitch to keep you in the recommended RPM range. If you are almost at sea level you can get away with a 21p and still get good RPM's. Higher pitch will get you more top end, lower pitch more holeshot.

hi Lars

I'll try & keep this brief. Aluminum is much less expensive and easier to repair than Stainless but Stainless tends to perform better. If you spend a lot of time in shallow water or debris littered water, i would consider buying an aluminum prop. I'm not sure what prop you have on your boat now but the key consideration is to keep the WOT maximum RPM's in the upper part of the recommended range for the best results and as bpfirrman states, lower pitch means better holeshot, higher pitch means better top end speed. Lower pitch also increases the WOT rpm's while higher pitch lowers them. For example, if you are running a 19" pitch aluminum prop and getting 45mph at 4800 rpm and change the prop up to a 21" pitch, your top end may increase 2-4mph and your rpm's should drop to around 4300-4400 (approximately). As Dudders says, there are so many variables that you could pick 3 props with the same pitch and get 3 different results.

If you want to go with Stainless there are plenty of good props out there. While Merc's own brands tend to be a little more expensive, they are well made props but each one is designed for a slightly different application so you need to read up on them carefully. Check out the Stiletto Bay Pro II as well as the ones you mentioned. Michigan Wheel and Solas are two other less expensive but popular brands.

btw.... i would expect Mercury to have good things to say (in their advertisements) about their own props! ;)

If you are going to change the prop on the water, make sure you invest in one of these....

http://247marine.com/shop/images/Pro...r%20Wrench.jpg

I think it was like $8 @ my local boat supply store. It floats. Something that was recommended to me by my uncle.

Thanks for good advices bpfirrman, mikeyt and 180diablo! I'm pretty sure that the propeller I have now is a 21" pitch, and it's alu. I get 52-54 mph at WOT with 4800 rpm (or slightly more)... And there is no need for better acceleration so I think I'm looking for a prop that gives me some more top end speed.

BTW: any of you guys tried to install trim tabs (such as Smart Tab SX) ?? are they any good or just bs?

Lars, If you aren't sure on the type of prop you have, look on the hub portion of the prop and you should see a part number and pitch would be stamped on there as well. The last 3 digits should be your pitch. I forget what all the rest mean. Feel free to post up what it says on your prop and we can identify it easier.

This should help you out. Below is a thread on the Smart tabs in the Original Mariah section. :wink_thumbup:

Click, Click

Thank you! I'm going to check the number, way to many jellyfish right now :(