Props?
 

I am guessing this topic has been discussed several times in the past but I haven't been a member that long and would like to ask it again. Looking for suggestions on props for all round use. Not interested in going real fast. Mainly just cruise and wakeboard. I would like a prop that really holds a constant speed even when towing a heavy boarder.

Assuming you have mercury power, one way to get a good idea is to see what merc recommends. You can use their prop selector tool:

http://appcenter.mercurymarine.com/propSelector/home.do

You will have to know the specifics about your engine type, drive ratio, WOT rpm, and current top speed. It should give you a good idea of where to start. You can adjust the selector tool to fit various preferences in term of what you are looking to get (top speed, watersports, acceleration, etc.)

As Z202 says...the Mercury prop selector tool is a good place to start. The thing you have to remember though is that you dont want your engine running outside the recommended RPM range at WOT. What engine do you have? What prop do you have on the boat now and what RPM's do you read at WOT?

With your 182 and i'm assuming you have a 4.3L engine, a 3 blade - 14.25" x 19 pitch prop will be a good start and a 20 pitch - 4 blade will give you a little extra bite. Also, as one of our other members noted, altitude affects engine & prop performance. SS props perform better than aluminum props but at a higher cost and cuz they are much harder there is more chance of damaging a drive shaft if you strike something solid. But.....a lot of this is trial & error along with some educated guessing so lets answer the initial questions & go from there.

MikeyT is correct, propping is not an exact science as I have learned. I recommend buying a prop from a local shop that will work with you to find the right one. They should let you test different props to find the one that gets you the performance you are looking for.

Hey Mikeyt, I see on several posts that you seem to be quite knowledgable on props so to answer your questions I have a 4.3LX with 14.25x19 as well as 21. The 19 works ok but is slightly damaged and I don't want to run it and risk damage. The 21 is probably the right prop for the boat as I can go about 50mph with 3-4 people at just under 5000RPM. The problem is that the boat is a dog with this prop and it is very hard to plane towing a skier/wakeboarder. I am not concerned with the over-reving problem as I am the only driver and will make sure to watch RPM...or I'll be buying an engine. I would be more than happy with 40-45mph if I could get a good wholeshot for wakeboarding and mid range power to hold while the boarder cuts back and forth hard. I think I would like to go to a 4blade based on reading on this and other forums but should I get an aluminum or SS and 19 or 20. My local dealers suck and won't work with me at all as far as trying props out so I need to do it right the first time. I realize there has to be some compromise, and in my case I am willing to sacrafice top end for bottom end and mid range performance. The next thing is that I need to source a prop ASAP from a local dealer that has stock so if you have a couple suggestions(brands) it would be appreciated.

Hi Kurtis

If you are already over the max RPM (4800) for your engine with a 21" pitch prop, dropping the pitch to a 19 will increase your RPM's by about 400 which will take you way over the limit. I would consider a 4 blade, 20" pitch SS prop to keep you RPM's within reason. There are a number of good brands out there but i would consider a Mich Wheel Apollo prop which seems to be good value for the money. The Stilletto Bay Pro is another good 4 blade prop.

Just out of curiousity...have you checked to make sure your tach is at the correct setting for a 6 cyl motor? Hitting 5000 rpm with a 21" pitch prop seems a little high.

I've checked the tach and it is in the correct setting. I've also turned it back and forth as per one of the posts in this forum just encase it was making poor connection etc. My 19" prop was a second prop that came with the boat and has a slight gouge in one of the blades....maybe I'm getting a lot of slip as well??? Don't know the history of the prop...definately not new. Looks quite old.

I am now being told that a 4 blade aluminum Mercruiser prop in an 18" pitch would be about the same as the 19" 3 blade for max RPM. That is what one local shop told me. Most shops around my parts recommend aluminum because of the small shallow lakes. This is a much cheaper option than SS in the event that I am not totally satisfied with it?

maybe i didn't understand earlier. Are you running the 19" pitch prop or the 21" pitch prop and getting 50mph @ just under 5000 rpm?

If its the 19 then yes an 18" 4 blade will be very close just as a 20" 4 blade will be very close to a 21" 3 blade. What you will get with the 4 blade is a little more 'bite' & low-mid range acceleration. You might lose 1-2mph off the top end.

There's no question an aluminum prop is a cheaper option if you are usually running in shallow or rocky lakes and there will only be a very slight performance loss so if that works for you then go for it. ;)

Sorry for the confusion. I was running the 21 to get 50mph at 5000RPM. So I realize I am going to over-rev with anything lower than that but I have not choice. I need the power. I haven't tried it yet but I am going to purchase an 18" 4blade aluminum which should be close to the 19 3 blade as you stated. I will just have to be carefull with RPM. I appreciate your insight....now if I could find a carburetor expert to chat with me in the Boating101 forum I would be in business?

Thanks