Rpm and top speed loss after changing reeds?

[1224bret]

Last year I installed a set of ccms fiber reed valves and had my injectors professionally cleaned all went back together and the motor runs great but I've lost 400 rpm after the change. Ran it last year thinking maybe the reeds needed to break in but nothing has changed. Before changing the reeds I was running 5600-5800 rpm now I'm around 5100-5200. The 250 in my signs the engine and the specs are 5000-5800 but I'd rather be on the upper end at least that's what I think would be better. Anyone else ever have a similar experience after changing reeds? Is 51-5200 rpm ok or should I re-prop? Running a 23 pitch mirage right now no issue with hole shot or any other issues. Ideas? Thanks

[THEFERMANATOR]

I would think the 23 pitch is way to much prop for even a 250 on a v-20. I ran a 17 pitch mirake knockoff on my 20 foot cc, and ran low 50's turning rpm's in the mid 5K range. I doubt the reeds caused you to lose rpm's, if anything I would have expected an increase. What sppeds are you running at what rpm's? Honestly I would think a 19 pitch would be where you would want to be at for a v-20 cuddy with a 225-250hp merc.

[1224bret]

Before changing the reeds and injectors I was running around 54mph at 5800 now I see around 48-50 at 5200 those speeds are all lightly loaded. Been thinking about going to a 19 just wasn't sure what would have caused the drop...

[1224bret]

Oops just realized I said 23 pitch I'm running a 21 pitch mirage right now not a 23 pitch

[THEFERMANATOR]

Your prop slip is REALLY high for both sets of numbers. 54 at 5800 is 13% prop slip, and 50 at 5200 is 10% prop slip. I would be rechecking your speed and tach as a mirage prop should have slip numbers in 4-8% range MAX, but many of us have seen slip numbers in the 0 to negative prop slip. I know mine ran -4% prop slip when I ran a mirage type prop.

[jvitiel]

How can you have negative prop slip? Sounds impossible unless you are going down hill no?