Reply
 
Thread Tools Search this Thread
 
Old 08 April 2008, 16:50   #1
Member
 
Country: UK - Scotland
Town: scotland
Boat name: tango
Make: looking
Length: 5m +
Engine: outboard
Join Date: Jan 2007
Posts: 50
sorry prop size again

delta 5.8 90 mar 2 stroke standard prop light load.
problem is that it gets to it full speed 35 knt easy but with loads of extra revs to spare. my thoughts are that if i was to change the prop to a bigger size or pitch, it should go faster and in turn give more economy at 35knt or am i talking a lot of s--t if not what size and has anyone got one for sale?
cheers
__________________

__________________
tango1 is offline   Reply With Quote
Old 09 April 2008, 15:59   #2
Member
 
Country: UK - England
Town: Looe
Make: Delta
Length: 4m +
Engine: Mercury
Join Date: Apr 2004
Posts: 1,335
When you say lots of revs to spare, do you mean its not revving high enough? Your engine should rev to about 5400rpm (i think from memory). So firstly you need to get the revs right. Putting a bigger prop on will make your top end quicker but also reduce your pick up, the engine will under rev and put extra strain on it as its working to hard and loose fuel economy. If its over revving you will loose top end but gain on pick up and again knacker your engine as its revving its tits off.
__________________

__________________
Turbodiesel is offline   Reply With Quote
Old 10 April 2008, 18:50   #3
Member
 
Country: UK - Scotland
Town: scotland
Boat name: tango
Make: looking
Length: 5m +
Engine: outboard
Join Date: Jan 2007
Posts: 50
hi

the engine over revs eg 5400 =35knts but it will go up to about 6000 with no further speed but i did let it it do 6000 for any of time! only a few secs. i understand it is the standard prop that came with the engine. i feel there is more power to be had out of this engine.
__________________
tango1 is offline   Reply With Quote
Old 10 April 2008, 19:16   #4
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
There will be a number on the prop. It should look something like 48-1235779-17P. The 2 digits before the P are the prop pitch. What do they say?
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 11 April 2008, 15:45   #5
Member
 
Country: UK - England
Town: Looe
Make: Delta
Length: 4m +
Engine: Mercury
Join Date: Apr 2004
Posts: 1,335
Quote:
Originally Posted by tango1 View Post
the engine over revs eg 5400 =35knts but it will go up to about 6000 with no further speed but i did let it it do 6000 for any of time! only a few secs. i understand it is the standard prop that came with the engine. i feel there is more power to be had out of this engine.
If it will rev to 6000rpm you will probably need to go up by 2 pitches.
__________________
Turbodiesel is offline   Reply With Quote
Old 12 April 2008, 16:43   #6
Member
 
Country: UK - Scotland
Town: scotland
Boat name: tango
Make: looking
Length: 5m +
Engine: outboard
Join Date: Jan 2007
Posts: 50
got it!

i was at the boat today this is what i found. 4877342A4515p. i hope this helps
thanks
__________________
tango1 is offline   Reply With Quote
Old 12 April 2008, 17:05   #7
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,013
Looks like you are running a 15" pitch prop which is why you are overevving, you could easily run 17" and or possibly 19" on that combo.
__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 12 April 2008, 19:26   #8
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
I think Chris is right. If you're using it for diving a lot and carrying a lot of people/gear then I'd start at a 17" pitch standard quicksilver ally prop.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 02:41.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.