Prop Stuff- Confused; 4.3 mercruiser

[Ki Ki]

Hello All... I have a 4.3 mercruiser lx in a Searay 175. The prop has been reconditioned but shows some bending at the blade tips. I tested it this weekend at WOT. I achieved 5000 rpm's and about 47 mph.

Here are my questions- is that too much RPM's? Seem right about speed? Why would I have that much RPM's? Boat runs great and is getting 47. Anways, I think I could get even better speed with a better prop.

Thoughts? I think it's a 14x23 pitch prop. Recommendations?

 

[alldodge]

Are you using GPS for speed and is your tach accurate?

 

[Scott Danforth]

doubt if you can get more speed out of it. verify your speed with the GPS

 

[QBhoy]

Hi
Rpms are a little high at 5000rpm, but will likely be brought down towards ideal with an undamaged stainless or ally prop.
For a stingray with a 4.3...you may even be a little low on speed. They have been well documented to run towards the 60mph mark gps with a 4.3 and decent prop.
There have been a few prop tests done on this model or similar (was a post on it earlier this year) with a 4.3 carb. From memory a tempest or trophy resulted in 60mph or just over.
Fast boats...I'll see if I can find the link to the test I posted on the earlier post.

 

[QBhoy]

http://www.stingrayboats.com/product...s/tb03_06.html
This was one article referred to.
There was another that referred to a stingray 195 with a 4.3 doing 63mph with a trophy 21 or 23" prop.
There is a stingray 195 in my marina on a dry berth. She rarely sees the water but on one occasion last year the owner had a wee go at my boat. Considering its modest 4.3, it was surprisingly fast. She was doing at least 58/59 before I managed to get by it.
I park the car next to it most weekends...looking at the hull it is easy to see why. Super sleek and shallow v. Most likely not great in the choppy conditions often seen here though....quick they are though.

 

[QBhoy]

http://forums.iboats.com/forum/gene...-out-prop-on-2005-stingray-after-long-storage

 

[Ki Ki]

Thank you. It's actually a Sea Ray, not Stingray. Not sure if that's what you meant. Yah, I'm getting about 48 mph with two people on board and 5000 rpm's with my stock prop, that has a little bending on one of the blades.

 

[ahicks]

If you have a bent prop and you're looking for more speed, it would seem to me like the bent prop would be a good place to start. Not just for the obvious necessary repair, but for what a good prop shop can do with that prop to get the rpm's lowered a little (if that's what you want). Talk to the prop repair facility. Ask them about it and give them the info you've given us. They can often work some pretty serious magic when asked to! Just keep in mind that your prop is a compromise as a rule. What you add on top will be taken from the bottom end (pulling power/hole shot).

 

[QBhoy]

Doh !
In that case ignore 90% of what I posted haha.