Mercruiser 5.0 Prop Reccomendation

This is a new boat with a stock prop. Not sure of the pitch. What can I look for to maximize speed yet still allow for decent to good speed out of the hole? 3 blade, 4 blade?

I know zilch about props.

Thanks

Re: Mercruiser 5.0 Prop Reccomendation

What kind of boat? You don't prop an 18ft boat the same as a 21ft boat with the same power plant.

The dealer most likely equipped it with the prop he always puts on "that" boat for good all around performance. You prop a boat so that the motor operates within its recommended rpm range, but lots of boats are slightly over propped because everybody wants SPEED.

There is no one prop that does everything. You'll want it to be at or near the top of the range for better acceleration for water sports; or near the lower part of the range(more pitch) for top speed.

The "right" prop is the one that fits your particular intended use. A general purpose prop might have more pitch than a prop intended for water sports.

If your general purpose prop is not giving you good acceleration(most don't), you need to get one the next size lower in pitch to get the good hole shot for pulling skier, etc. For example, if the original prop is a 21", a 19" pitch should do the job.

Re: Mercruiser 5.0 Prop Reccomendation

Thanks. It's a Tahoe Q7i, 5.0 MPI Mercruiser.

Re: Mercruiser 5.0 Prop Reccomendation

What would help is some information. What are the rpm's of the engine when it is wide open throttle (WOT) rpm's? What is the speed when WOT? What is the pitch on the current propeller? What is the gear ratio on the lower unit? All of those can help determine a good propeller. There are many different types of propellers. Check out the icon at the top of the screen "Boat Propeller Tips."

Re: Mercruiser 5.0 Prop Reccomendation

The Tahoe is a "package" boat that comes from Tracker Marine all set up, including a prop already on it.

Since this is not their first rodeo, they are pretty good at equipping the boat with the correct "general purpose" prop, meaning the one that lets the motor operate within it's recommended rpm range(in this case 4600-5000), while allowing the most top speed, since that's what most folks are interested in.

While the Mercury prop selector says a 19 pitch for this boat, I wouldn't be surprised to see a 21 on there, for the reason mentioned. It would allow for the most speed with a light load.

Until you tell us what WOT rpm this prop does(as well as the prop size) we cannot say whether or not it might be appropriate for whatever your intended use is.

If the boat is "new", you should take prop selection up with your selling dealer, who should be happy to swap out a different prop if a test determines it appropriate for what you are trying to accomplish.

Re: Mercruiser 5.0 Prop Reccomendation

Thanks for all the responses. I will be taking it out this weekend and will find some answers to these questions. I suppose for most speed, it probably would be what's on it but I was more looking to increase my out of the hole speed and staying on plane at lower RPM's to better play, kneeboarding, etc. From what I read, a 4 blade could help with that. But from the responses above, I see there are a lot of other factors I need to know to better find a solution.

Thanks again for the information and I'll begin the process.

Re: Mercruiser 5.0 Prop Reccomendation

Just to touch on the 4 blade It is usually considered to improve hole shot and stay on plane easier at reduced throttle.
It may improve handling around the dock,can reduce ventilation.Usually expected to reduce top end a little.
Depending on the present rpm simply going to a lower pitch can improve hole shot and help stay on plane a little better
and may not sacrifice as much speed.
Of course there are all kind of designs and configurations that can improve performance some cost thousands of dollars.

Re: Mercruiser 5.0 Prop Reccomendation

I have a 19" pitch SS on my 21 foot 5L MPI. Its smooth, planes well and steering isn't too bad either.