Re: buying a prop need help
 

I have exactly the same boat (it is actually for sale). I have tried a number of props and have three excellent combinations depending on the application. The setup is a 5.7l merc and an alpha 1 drive. Max RPM is 4600 on the motor nameplate. Let me know you interested and I will get you the exact numbers. The aluminum I use as an all around "ski or loaded up with weight" prop is a 19P * 14 1/2". This turns on plane at 3200 RPM so it is a little tougher on gas. I also have a 21P * 14 1/2" for light loads and gas saving in aluminum. It spins around 2800 RPM on plane. You won't get on plane with 6 people and gear with that one. The best fit is an odd ball stainless from mercury and I believe it is a 19P * 15 1/4". It gets the best top end right at 4550 ish and 50 + MPH on a smooth day. It turns around 2900 - 3000 RPM on plane. Just not a great prop to run in unknown waters as the stainless won't give if you hit something and likely f@$ the outdrive. I have access to a lot of props through a friend and this is what I have found work the best.
The 23P * 14 1/2" sounds like too much unless you have a different motor or gearing in the outdrive.

Let me know if you want the exact model #'s of props and I can look them up. Or you could buy my boat as the props come with it.:)

Re: buying a prop need help
 

Oh and by the way I agree if you hit the throttle and the motor revs up like it is slipping or out of gear you have rounded off the hub kit that fits inside the prop and it is going to get worst until you just can't go anymore. 30 - 50 buck fix. That is what they are made to do if you run it into the bottom or hit something. If you take the prop off and the hub is metal and has splines than it is something else going on.

Re: buying a prop need help
 

I also have a question about regarding a prop. I just took my boat out for the very first time today and for my motor i am supposed to keep it in the 4500 rpm range. At that rpm range i am running about 40mph and I only have the throttle about 3/4 of the way down. It still has alot of throttle let in her but it will run the rpms up way to high. Right now it has a 3 blade prop on it but i am unsure of the pitch and diameter. Do you have any suggestions for what i can put on or do to use the rest of the throttle that is left unused?

Re: buying a prop need help
 

It sounds like you are under pitched with the prop you have, but you need to know its pitch.:confused: The prop should have the pitch stamped on it. If not, you need to barrow a prop of a known pitch and retest so you have a known starting point to work from.

Re: buying a prop need help
 

4500 rpm at 3/4 throttle? hmmm....either you are underpitched or the tach isn't set correctly. First, access the backside of your tach and you will see a small dial which allows you to set the tach for the # of cylinders your engine has. Yours (obviously) is 6 so spin the dial a few times (but wait for Bob Barker to say "Come on down!") then set it on 6. :)

As for the prop it should be a 19" or better still a 21" pitch and the diameter & pitch is usually stamped on the backside of the prop around the hub. Some just have a model # stamped there so you have to look them up on the Merc site. If your tach is working correctly and you're still hitting those rpms at 3/4 throttle then the prop is likely a 17" or possibly a 19". At that point i would suggest finding a 21" prop and seeing where your rpms are at WOT. You want to keep your rpms at the upper end of the recommended range (4400-4800) at WOT for the best performance. You could move to a 20" pitch 4 blade prop also but the 21" - 3 blades are easier to find. Note though, there are always trade-offs when changing the prop pitch. Going higher in pitch results in lower rpms and increased top speed but at the cost of some low end 'grunt' and going lower in pitch has the opposite effects. The diameter shouldn't be an issue as it will be around 14" in this range.

Re: buying a prop need help
 

I agree with the above comments. If you do find that it is a lessor pitch (17, 19) and you are missing out on that top speed don't get rid or trade your existing one right away. Someone may have put that on there for skiing or tubing as you will get a bunch more pull out of the hole with the less aggressive pitch. The only problem is if you have 1/4 throttle left once you get going, you will have to really watch that you do not over rev the motor. If the tach is right you can likely get that motor over 5000 RPM and that gets real hard on things for any extended period of time. Once you get flying on the water it is easy to lose track of the dash because you start to be more worried about what is coming at you and the bulge in your pants.
I keep two different props in the Davanti and swap them out depending on the day and activity. One is good on gas and has a little more top end speed and the other lets you get out of the hole and going faster.

Re: buying a prop need help
 

Alright thanks i will check both and get back to you possibly later today with that info.

Re: buying a prop need help
 

Mikey, what are you running on the 180? I have a 183 and I want to get a prop that is good for tubing and loaded operation.. Anyone have recommendations here? I am all ears:horns::horns:

Re: buying a prop need help
 

Alright i took a look at my boat the tach gauge is set correctly i checked that out and my prop has a stamp of "191619P quicksilver" on it. So any more suggestions? Thanks for all the help and opinions guys.

Re: buying a prop need help
 

22 empire: I'm running a 20" pitch 4 blade SS prop most of the time since we tend to do a fair bit of wakeboarding and just running between the islands north of Parry Sound. If i'm going on a longer cruise, say along the shoreline of Lake Ontario, i usually swap to a 21" 3 blade aluminum prop for the higher top end and better fuel economy.

Irace: that looks like a 19" pitch prop so i would suggest looking for either of the props i mentioned above. The 4 blade should lower your rpms by about 1-200 and the 21" prop should drop the rpms by 3-400. The 19" will work fine for wakeboarding & skiing, the 21" (either aluminum or SS) will work fine for cruising. The 20" is kind of a mix between the two. It also depends on how much $$ you can afford to spend. A SS prop will give slightly better performance than an aluminum prop but at a higher initial cost.