Go Back  Offshoreonly.com > Technical > Prop Talk
Proping a 1987 Scarab III >

Proping a 1987 Scarab III

Notices

Proping a 1987 Scarab III

Thread Tools
 
Old 06-29-2008 | 09:35 AM
  #1  
Thread Starter
Gold Member
 
Joined: Oct 2006
Posts: 43
Likes: 0
From: Newark, DE
Default Proping a 1987 Scarab III

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,
siearly is offline  
Reply
Old 06-29-2008 | 10:17 AM
  #2  
Registered
 
Joined: Jan 2007
Posts: 192
Likes: 0
From: Laplace,LA
Default

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
fast22 is offline  
Reply
Old 06-29-2008 | 05:51 PM
  #3  
Scarab3DMC's Avatar
Registered
 
Joined: Apr 2001
Posts: 1,849
Likes: 4
From: Boynton Beach FL
Default

22-23'' Hydromotive's gave 60 mph..thats about it..Now however I running 28'' but new 600 hp power..
Attached Thumbnails Proping a 1987 Scarab III-100_0133-small-.jpg   Proping a 1987 Scarab III-100_0190-small-.jpg  
Scarab3DMC is offline  
Reply
Old 06-30-2008 | 05:27 AM
  #4  
Thread Starter
Gold Member
 
Joined: Oct 2006
Posts: 43
Likes: 0
From: Newark, DE
Default

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 is offline  
Reply
Old 06-30-2008 | 08:23 AM
  #5  
Thread Starter
Gold Member
 
Joined: Oct 2006
Posts: 43
Likes: 0
From: Newark, DE
Default

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?
siearly is offline  
Reply
Old 06-30-2008 | 07:59 PM
  #6  
bbladesprops's Avatar
Offshoreonly Advertiser
20 Year Member
Offshoreonly Advertiser
 
Joined: Jun 2003
Posts: 3,878
Likes: 47
From: Princeton, Wisconsin
Smile

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
__________________
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
bbladesprops is offline  
Reply
Old 07-01-2008 | 08:40 AM
  #7  
Thread Starter
Gold Member
 
Joined: Oct 2006
Posts: 43
Likes: 0
From: Newark, DE
Default

I will call this morning. Thanks.
siearly is offline  
Reply
Old 07-01-2008 | 09:24 AM
  #8  
Scarab3DMC's Avatar
Registered
 
Joined: Apr 2001
Posts: 1,849
Likes: 4
From: Boynton Beach FL
Default

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..
Scarab3DMC is offline  
Reply
Old 07-01-2008 | 09:52 AM
  #9  
bbladesprops's Avatar
Offshoreonly Advertiser
20 Year Member
Offshoreonly Advertiser
 
Joined: Jun 2003
Posts: 3,878
Likes: 47
From: Princeton, Wisconsin
Smile

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

Brett
__________________
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
bbladesprops is offline  
Reply
Old 07-11-2008 | 05:35 AM
  #10  
Thread Starter
Gold Member
 
Joined: Oct 2006
Posts: 43
Likes: 0
From: Newark, DE
Default

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.
siearly is offline  
Reply


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.