Reply
 
Thread Tools Search this Thread
 
Old 18 November 2008, 14:24   #1
Member
 
TonyC's Avatar
 
Country: UK - Wales
Make: XS // Delta
Length: 6m +
Engine: 60hp // 2x90hp
Join Date: Feb 2007
Posts: 213
Honda 50 - prop?

I just want to get some thoughts from others on here about our rib

We have a honda 50hp on the back, and WOT atm only produces about 4500-4700 rpm (manual says max range is 5500-6000rpm)

It currently has a standard 13in prop on it and I know that if I drop the prop size, it should increase the revs, but is this the only option? (12in prop seems a bit small to me?)
__________________

__________________
TonyC is offline   Reply With Quote
Old 18 November 2008, 16:10   #2
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
Whats the boat?
__________________
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 18 November 2008, 16:12   #3
Member
 
Country: UK - Wales
Town: West Wales
Make: Vipermax 5.8, SR4.7
Length: 5m +
Engine: 150 Opti, F50EFi
Join Date: Sep 2005
Posts: 6,298
If you provide a bit more information, people may be able to help.
e.g.
What boat is it?
What loading when you get restricted max RPM?
Has it always been like this?
What age/hours on the engine? Has it been serviced recently?
Is the propeller in decent condition?

I could ask another dozen questions, but these should be good for a start.
__________________
Downhilldai is offline   Reply With Quote
Old 18 November 2008, 16:28   #4
Member
 
TonyC's Avatar
 
Country: UK - Wales
Make: XS // Delta
Length: 6m +
Engine: 60hp // 2x90hp
Join Date: Feb 2007
Posts: 213
It's an XS 5m. Loading isnt coming into play, as whether its one up, or four up, it's the same.

It's been like it since it was married with the boat. Engine is a couyple of years old, but only had minimal hours & use put on the engine before being put into storage. Since going on this boat, its had about 120 hours on the engine.

The engine was serviced in April when it was taken out of storage and put on the RIb, and the prop is in near perfect condition.
__________________
TonyC is offline   Reply With Quote
Old 18 November 2008, 19:12   #5
Member
 
Country: UK - Wales
Town: West Wales
Make: Vipermax 5.8, SR4.7
Length: 5m +
Engine: 150 Opti, F50EFi
Join Date: Sep 2005
Posts: 6,298
Strange that it's not making more max RPM when lightly loaded.

Is the motor getting max throttle on the carbs? Perhaps the throttle cable needs adjusting?
__________________
Downhilldai is offline   Reply With Quote
Old 19 November 2008, 11:50   #6
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
How does it get up out of the hole?

You're about a thousand rpm low; if it's only the prop, you'd think it would take forever to get on plane.

FWIW, my buddy is running a 16' Zodiac RIB with a Merc 60 4-stroke, and runs a 12" 4-blade SS prop.

jky
__________________
jyasaki is offline   Reply With Quote
Old 19 November 2008, 12:04   #7
Member
 
TonyC's Avatar
 
Country: UK - Wales
Make: XS // Delta
Length: 6m +
Engine: 60hp // 2x90hp
Join Date: Feb 2007
Posts: 213
Gets up on the plane just fine, revs arent noticibly different when a few up (dont think ive ever had it fully loaded)

Thats sort of why I was wondering. in general the boat seems to perform just fine with the current prop at the revs it reaches, im just wondering if it could be something else.
__________________
TonyC is offline   Reply With Quote
Old 20 November 2008, 12:13   #8
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
First thought: I'd be looking at the throttle control not fully actuating the throttle at the motor.

Should be fairly easy to test: Pull the cover, see what moves when you change the throttle position, set to WOT, and see if you can move the parts more. You can verify by doing the same thing on the water (have someone else move the part, or steer the boat - not a one-man job.)

jky
__________________

__________________
jyasaki 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 23:39.


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