I'm stumped. Any ideas ?

[Darbster]

I have a 2000 20XD with a 225 pm w/sportmaster foot. I have a 25 TXP that I have run 83 mph in this heat with a full load and a partner in boat , I also have run 85mph by myself with some more left in it. This is at 1.25 above the pad. I also have a 26p chopper from factory that runs 81 at 6900rpms. I also have a 28p chopper from factory that would only run 78 mph out the box at 6900 rpms. It wouldn't lift front of boat enough.
Today I got the 28p prop back from baggy. It looks amazing would never think it's the same prop. I ran it today at 7100 rpms and could only get 80.5. An improvement but not near what I expected. I raise motor to 1.75 above the pad and it would only run 78 mph. I am confused. Bigger wheel more rpms raised motor and less speed
I was turning 7200 rpms and it felt like it would blow out at any minute. Why would a 25 TXP outrun a 28p chopper?



Modified by Darbster at 5:10 PM 8/18/2010

[Cooney]

1.75 " above the pad seems kind of high for the TXP, I realize you have a 20 footer, but I'm runnin' mine about 1/4" below to even with the pad( hydraulic plate) After that it doesn't gain much more. But I'm also running a 21 footer.

[Darbster]

i have a sportmaster foot, I run the TXP at 1.25 above the pad. i raised it for the choppers after the initial run , I have only went to 1.5 above with the TXP

I cant figure this out . I have yet to run a 3 blade prop that does well on this boat.

[BARRY J]

You might be too high and losing bite. I would try lowering it to even or maybe 1/4 inch below and try again.

[Cooney]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by BARRY J &raquo;</td></tr><tr><td class="quote">You might be too high and losing bite. I would try lowering it to even or maybe 1/4 inch below and try again.</td></tr></table>That's what I was trying to say, but he's in a 20 footer, has a lot less nose weight than I do, and that sporty likes to ride high, But if it feels like it wants to let go, your probably to high.

[Darbster]

when i went to pickwick we lowered it to 1/4 in above and the prop i tried still wouldnt run more than 76 on my boat and 86 on buddy's boat ( he had same boat but a modified CLE foot). i will try to lower this one and try again tomorrow. i have 18psi water pressure at 1.25 above and 16psi at 1.75 above.

I beleive that the 1.25 is ideal height for performance, but everyone is saying it should be faster, and to raise it.

[BARRY J]

With a sportsmaster, you will run out of bite long before you run out of water pressure.

[Cooney]

I understand about the water pressure, but if the prop won't bite, it'll cause a lot of slip and your just throwing water, How high is the rooster tail??? shouldn't be no higher than your engine cowl

[Rebel1]

What kind of load do you have in the boat when running the Chopper? Those props are not good for carrying any kind of load.

[Darbster]

I do believe that the 1.75 above was too high. it was throwing a wide rooster tail, water was going everywhere, wider tail than the motor was wide , it looked weird and felt weird, had alot of vibration at that height. it felt perfect at the 1.25 but just not speed i should be turning with a 28P prop and 7100RPMs.

I will go fishing probably in morning will leave it on boat and see how it does with load. lowered to 1.5 when i got home will lower to 1.00 in morning and see what happens.

[Darbster]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Rebel1 &raquo;</td></tr><tr><td class="quote">What kind of load do you have in the boat when running the Chopper? Those props are not good for carrying any kind of load.</td></tr></table>

I had boat with my fishing tackle, no water in live well, about 3/4 tank of gas, and about 70lbs balast on passenger side.

[timmaahh12]

What's a "CLE" lower unit?

[Darbster]

the crazy part is that at the 1.25 height :
25TXP@6900RPMs runs 82-83 with load and 2 people
runs 85+ by myself with fishing load

26Pchopper @6900RPMsruns 79-80 with fishing load and partner
@6900RPMs runs 82-83 with fishing load by myself

28P chopper@6900RPMs ran 77-78 by myself before worked wouldnt lift front
@7100RPMs ran 80.5 by myself fishing load(after worked)

raised motor to 1.75 above ran 78mph @7200 RPMs

so smaller props outrunning bigger props CRAZY

[Cooney]

Yea, but I'll bet that's cause that TXP won't flex like the chopper giving you more bite. Slip has a lot to do with it...

[AndrewWilson19]

I thought the un wrote rule was 3 1/2 below pad? Are or y'all talking bout something else?

[Darbster]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by timmaahh12 &raquo;</td></tr><tr><td class="quote">What's a "CLE" lower unit?</td></tr></table>

someone else could answer better but it looked almost like a reg foot with a bobs nose cone for low water pickup, and it was black not grey like sportsmasters

[Cooney]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by AndrewWilson19 &raquo;</td></tr><tr><td class="quote">I thought the in wrote rule was 3 1/2 below pad? Are or y'all talking bout something else?</td></tr></table>We're talking about performance hulls, a lot of difference between Bullet and Ranger.

[Rebel1]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by AndrewWilson19 &raquo;</td></tr><tr><td class="quote">I thought the in wrote rule was 3 1/2 below pad? Are or y'all talking bout something else?</td></tr></table>

You have alot to learn young one......

[RogerR]

Get a SKEETER Darby

[Rebel1]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Cooney &raquo;</td></tr><tr><td class="quote">Yea, but I'll bet that's cause that TXP won't flex like the chopper giving you more bite. Slip has a lot to do with it...</td></tr></table>

The TXP is just giving you more lift, thus less wetted surface and more speed.