Proping a 1987 Scarab III

[siearly]

Hi,

I'm looking for advice and suggestions. Here is what I have:

1987 Scarab III

454's, I don't know how much HP they're making but they are carbureted and probably have a modifed cam

boat has bottom paint

TRS drives

Last year I was running Stern Driver 22 inch 4 blades which gave decent hole shot and top end but since my tachs were inaccurate and one prop was damaged, I don't have good numbers for performance.

This year I installed Mirage 23 pitch 3 blades, which I painted, and new instruments.

I have great hole shot and top end is 50 mph at 4,900 rpms. I run 32 mph at 3,700 rpms and 40 mph at 4,100 rpms. If I try to run 3,400 rpm she wants to fall off plane. This is with just under 1/2 tank of gas (a tank is 200 gals), two adults, one child, and our overnight gear.

I would rather see more speed at less rpms and feel like I'm under propped. Would you agree?

Can I get my current Mirages re-pitched to say 24" or do I need to run different props?

Thanks,

[fast22]

Some four blade bravo1's would deffinetly help with the low speed and midrange criuse, and with the bow lift they provide, it will probably keep it from falling off of plane with a load. I'm not positive but I think when you go to a 4 blade from a 3 you have to drop 2 pitch. So maybe some 21 bravo's and go from there. I'm not very familiar with the TRS drive setup so maybe someone with a little more experiance will chime in.
Scott

[Scarab3DMC]

22-23'' Hydromotive's gave 60 mph..thats about it..Now however I running 28'' but new 600 hp power..

[siearly]

Originally Posted by fast22

I'm not positive but I think when you go to a 4 blade from a 3 you have to drop 2 pitch.
Scott

Oh I see. That might explain my high rpms and low speed with the 3 blades I'm currently running. I only went up 1 inch in pitch when I went from 4 blade to 3.

So I'm wondering, should I go back to 4 blade 22 inch or stay with 3 blade and go to a 24 inch?

[siearly]

Originally Posted by Scarab3DMC

22-23'' Hydromotive's gave 60 mph..thats about it.

Do you have any speed/rpm figures from when you were running the smaller pitch Hydromotives?

[bbladesprops]

You painted your props?

We can supply you with some 21 Revolution 4 propellers and life is good. You will stay on plane at lower rpms.

If you want to test them, give us a call.

B

[siearly]

I will call this morning. Thanks.

[Scarab3DMC]

Originally Posted by siearly

Do you have any speed/rpm figures from when you were running the smaller pitch Hydromotives?

yes give me a day or two..Mine ran (with the stock 502's) Hydro's Q-VI's 22-23" pitch..

[bbladesprops]

Nice speaking with you today. We will get the test props out Thurs.

Brett

[siearly]

Originally Posted by bbladesprops

Nice speaking with you today. We will get the test props out Thurs.

Brett

Brett,

Props arrived yesterday. Of course, I'm no expert but they look brand new to me.

I'll be mounting them tonight and doing some test runs.

I did find out that I do not have rev limiters on my engines so I'm hoping we didn't go with too much pitch. But hey, even if we did your exchange program makes that a simple fix.

Thanks for all your help and I'll let you know what happens.