props
 

I have a 26 pitch prop on my 29' fever and am only turning 4800 rpm@WOT. If I go down to a 25 will I pick up speed because of the raise in RPM? Any thoughts would be greatly appreciated.

lab your 26
Call houston prop

You left out some stuff. What was your trim setting and tab settings. What year is your hull? What engine? If someone out there has the same configuration it might be interesting to know what they are running at. What condition is your prop in.

I just learned that props can be off in diamater and pitch by a lot when they are brand new. So buying a new 25 pitch (3 or 4 blade?) may not get you to where you want to be. You can have your existing prop "tuned" to maximize rpm vs speed.

Going down in pitch may give you more rpm's (probably will) but if all else is not in order (tune up, dirty intake plenum or air cleaner) it may not give you more speed.
A good thing to do after you check all the other stuff out is borrow one if you can.


Just a few thoughts, I am by no means an expert.... Check the mercury home page out, I remember they had some basic info somewhere in the prop section.
good luck....

That sounds like you're all balled up.

The new 29's come with a 26 pitch & they spin past 5000 no prob. Past 5200 even.
What's causing your RPM to hold up?

As NL said, where are your tabs & trim?

A few other variables, temperature, altitude, weight (fuel and pax), salt or fresh water? HP, year and condition of your engine, and the list goes on. You should get a lot of response to your thread that will be very useful but you need to give as much detail as possible. Good luck.

G-

Thanks for the info guys, the boat is a 1997 Fountain Fever 29'. The engine is a 525SC. 26 pitch 4 blade prop. Tabs are all the way up, trim is all the way out. 5 psi boost. The motor is all stock with 320 hours on it. The prop is in excellent condition. Half a tank of gas.

When did you get the boat? Has it always topped out at 4800 RPM?

what gear ratio?

I have the same boat and originally had the same set-up. I moved to an IMCO Extreme and 2" Shorty and a smaller pulley and now turn a labbed 30P Bravo 5100 rpm at 7lbs boost. Much better handling, etc.

You definitely should be turning more rpm's - check: (i) plugs & wires; distributor cap & rotor; s/c belt - all could contribute to the low rpms. then look into labbing the prop.

I have a 2000 29' with an HP500 EFI. Stock prop from Fountain is a 24p Hydro. Per the performance report, the boat did 74.5 mph @ 5300 rpm. Best I have seen is 73.2 mph @ 5300+ (bouncing offf rev limiter once or twice) in salt when I sea trial'd the boat, but that was with 2 semi-large adults, near full tank of fuel and a bunch of other $hit in the boat. That was also my first time ever driving this particular boat. I run the boat in freshwater now and the best I see is 70.2 with about the same overall load, and I still hit the rev limiter occasionally, trying to get the last little bit out of it - and probably a little over trimmed. I have a brand-new 25p Hydro that I have tried and it brought the rpm's down to about 5050 - 5150 and the top end mph stayed just about the same. Cruise at 3000 rpm went from 37 mph (gps) to 40 mph, which is great, but you can feel/hear it loading the motor harder. Also, getting on plane seems to be loading the motor much more with the 25p, and it is noticeably more sluggish getting on plane. I put the 24p back on the boat for "general" use because I think it is easier on the motor. I might get the 25p labbed or see if I can get it pitched to 24.5p, if they can pitch it .5 inches. ;)