Like Tree0Likes

New motors suck!!

Reply
Old 04-23-2002, 12:42 AM
  #1
CBR
www.hyperfishing.com
Platinum Member
Thread Starter
 
CBR's Avatar
 
Join Date: Oct 2000
Location: North and South
My Boats: Sonic 30ss
Posts: 1,974
Default New motors suck!!

Okay guys, I need help. I had some scorpions installed in my 1988 Sonic 30SS and top speed is a mere 62 MPH on full fuel and water tanks in fresh water. WHAT THE H...????

Anyone with any ideas? Oh yeah, I also had the X dimension raised one inch as per Sonic recommendation.

Swapped my old Ballistics with Bravo I props, I few more revs with the Ballistics and the best speed of 62 MPH.

Similar weight boats in Powerboat mag with scorpions are doing 77 MPH!! I expected at least 71 without a stepped hull.

Obviously, a compression test of the motors is in order first.

Bummed out.
CBR is offline  
Reply With Quote
Old 04-23-2002, 12:50 AM
  #2
speel chekk this fokker!
Charter Member
 
puder's Avatar
 
Join Date: Feb 2001
Location: Locust Valley, New York
My Boats: 27' Scarab
Posts: 5,329
Default

sorry to hear man that sucks!!!

are you spinngin eth props fast enough? what RPMs are your engines at?
__________________
Pardon me, while I whip this out!
puder is offline  
Reply With Quote
Old 04-23-2002, 01:10 AM
  #3
Registered
 
28Eliminator's Avatar
 
Join Date: Dec 2001
Location: Rapid City SD
My Boats: 1998 28' Eagle XP
Posts: 807
Default

Yea CBR, give us some more info. RPM's, Props, timing. Do both engines run the same? How well does it come on plane? Were the engines new, rebuilt or used?
Nothin worse than spending a bunch of money on something and being disappointed with the out come.
28Eliminator is offline  
Reply With Quote
Old 04-23-2002, 01:31 AM
  #4
CBR
www.hyperfishing.com
Platinum Member
Thread Starter
 
CBR's Avatar
 
Join Date: Oct 2000
Location: North and South
My Boats: Sonic 30ss
Posts: 1,974
Default

Revs were right at 5,000 and the Scorpions max out at 5200 so that is not the problem. Props were recommended by Sonic also, so that is not the prob. either.

Anyone running 350 HP scorpions in a 7,000 pound boat? The prop slip formula says 71 MPH, and the mag tests are over 75 MPH in similar boats.

I don't get it!
CBR is offline  
Reply With Quote
Old 04-23-2002, 02:31 AM
  #5
Registered
 
Join Date: Sep 2001
Location: Cucamonga
My Boats: 24 Hallett, 40 Hallett
Posts: 439
Question

Do you have a speedo or GPS ?
burtandnancy is offline  
Reply With Quote
Old 04-23-2002, 07:27 AM
  #6
jr
Guest
 
Posts: n/a
Default

CBR, what prop slip numbers are you seeing, what size prop. I'm running a pair of small blocks in my Nova II. The boat weighs in at about 6000 with full fuel. My engines are putting out around 425 HP. The problem I'm having is getting the props hooked up. I'm running an X dimension 2 inches higher than stock and I'm seeing prop slips upwards of 25% and a top speed of 59 GPS. Looking at the geometry of the bottom I have 2 blade tips out of the water by about 3 inches when I'm on plane. This year I'm putting on smaller diameter props and higher pitch. I've got 22"p Hydromotives now, and the boat doesn't really like them too much. I have problems getting out of the hole and I've had some blow out and my revs are way too high. So high that my secondaries dont come on until 5000.
 
Reply With Quote
Old 04-23-2002, 08:01 AM
  #7
Registered
 
Pure Energy's Avatar
 
Join Date: Oct 2000
Location: N. NJ, Eastern LI
My Boats: 2001 Superboat Y2K
Posts: 3,027
Default

Sorry to hear about the problem! This may sound funny but do the engines sound like they are running 5000 rpm? Is it possible the tachs are not accurate and you not getting WOT? Try a pair of 3 blades. I have a set of 23 Mirages you can try. Are you able to get enough trim? These boats need to be out of the water to get moving. Maybe lowering the X has something to do with it. If all else fails you might try 1" spacers in the drives.

I know it sucks but stay calm we'll figure it out.
Pure Energy is offline  
Reply With Quote
Old 04-23-2002, 09:04 AM
  #8
turbo2256
Guest
 
Posts: n/a
Default

JR ,
Have you tried some surface piercing props worked on an Alpha SS I had... or some drive spacers.
 
Reply With Quote
Old 04-23-2002, 09:52 AM
  #9
Platinum Member
Platinum Member
 
CigDaze's Avatar
 
Join Date: Jun 2001
Location: St. Petersburg, FL
My Boats: Cigarette 35 Cafe Racer
Posts: 21,346
Default

CBR,
What motors were in there before? Were they bigblocks?

If so, why was the x-dimension raised...less weight back there would mean that the boat would already be sitting higher than previous. Just a thought...
CigDaze is offline  
Reply With Quote
Old 04-23-2002, 10:15 AM
  #10
Registered
 
eyezlee's Avatar
 
Join Date: Feb 2001
Location: Broken Arrow/Grand Lake, OK
My Boats: SOLD!
Posts: 1,797
Default

Let me be the first to ask. Without trying to offend, why not Big Blocks?
eyezlee is offline  
Reply With Quote
Reply

Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
302Sport
General Boating Discussion
22
09-19-2008 02:19 PM
32 thunder
General Boating Discussion
17
07-09-2005 11:09 AM
tanned fat looks better
General Boating Discussion
6
02-19-2002 10:38 AM



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 05:54 PM.


Copyright 2011 OffShoreOnly. All rights reserved.