Reply
 
Thread Tools Search this Thread
 
Old 30 July 2008, 16:24   #1
Member
 
Country: UK - England
Town: Falmouth.
Boat name: Stingray.
Make: Predator.
Length: 6m +
Engine: Out, petrol, 2x90hp.
Join Date: Mar 2008
Posts: 36
Yam F100 problems.......loud knocking noise.

Well, during a run the other day the port side engine started knocking. Sounds quite loud so I come back on one engine. It sounded like a dropped valve or a big end.

Had another listen today, it starts ok, but knocks heavily. Removing one plug cap at a time, 1 or 2 makes no difference to engine running but quietens the noise. Removing cap 3 or 4 and the engine won't start, so it does point to maybe a couple of valves in 1 or 2 bent or broken springs etc.

Does anyone have any ideas/experience?

Does anyone have a working powerhead for sale in case mine is gonna be expensive?

I'll be looking more closely at the weekend.
__________________

__________________
Okeanos is offline   Reply With Quote
Old 30 July 2008, 18:03   #2
Member
 
Country: UK - England
Town: London
Length: no boat
Join Date: Dec 2003
Posts: 378
Has the cam belt been changed at the correct interval?
__________________

__________________
Rich L is offline   Reply With Quote
Old 30 July 2008, 18:17   #3
Member
 
Country: UK - England
Town: Bristol
Make: Ribcraft
Length: 5m +
Engine: Yamaha
Join Date: May 2006
Posts: 4,194
this would be a easy one, do a compression test on all cyl to establish what the compressions are or should be, that will tell you what to do next,
__________________
matt h is offline   Reply With Quote
Old 30 July 2008, 19:09   #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
Quote:
Originally Posted by Rich L View Post
Has the cam belt been changed at the correct interval?
Won't make any odds. A cam belt going will stop the engine dead. If it's still turning the valves it'll sound fine.



Pull the plugs and look for debris. Turn it over by hand and look down the plug holes with a torch,and do a compression test. It sounds like there won't be any quick fix though.
__________________
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 31 July 2008, 05:58   #5
Member
 
Country: UK - England
Town: Falmouth.
Boat name: Stingray.
Make: Predator.
Length: 6m +
Engine: Out, petrol, 2x90hp.
Join Date: Mar 2008
Posts: 36
Quote:
Originally Posted by Nos4r2 View Post
Pull the plugs and look for debris. Turn it over by hand and look down the plug holes with a torch,and do a compression test. It sounds like there won't be any quick fix though.
Will do that, if I don't find anything I'll remove the powerhead and then see what I can find stripping it down.
__________________
Okeanos is offline   Reply With Quote
Old 02 August 2008, 12:44   #6
Member
 
Country: UK - England
Town: Falmouth.
Boat name: Stingray.
Make: Predator.
Length: 6m +
Engine: Out, petrol, 2x90hp.
Join Date: Mar 2008
Posts: 36
Big ends have gone on cyl 4 and 3. No. 4 has about 1mm movement!!!

Expensive I think, second hand powerhead if I can find one.
__________________
Okeanos is offline   Reply With Quote
Old 03 August 2008, 06:38   #7
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
What about grinding the crank? May be a cheaper option than a replacement powerhead, depending on the condition of the rest of the motor.
__________________
Downhilldai is offline   Reply With Quote
Old 03 August 2008, 07:36   #8
Member
 
Simon B's Avatar
 
Country: UK - England
Town: Leicester
Boat name: Vixen
Make: Ribcraft
Length: 6m +
Engine: Suzuki OB 175
MMSI: 235071839
Join Date: Jun 2004
Posts: 1,621
Did they make to F100 in large numbers? I'd heard it was discontinued and replaced by a commercial version F90, do not know if this power head is the same though.
__________________
New boat is here, very happy!
Simon
www.luec.org
Simon B is offline   Reply With Quote
Old 03 August 2008, 12:57   #9
Member
 
Country: UK - England
Town: Falmouth.
Boat name: Stingray.
Make: Predator.
Length: 6m +
Engine: Out, petrol, 2x90hp.
Join Date: Mar 2008
Posts: 36
Quote:
Originally Posted by Downhilldai View Post
What about grinding the crank? May be a cheaper option than a replacement powerhead, depending on the condition of the rest of the motor.
I've suggested that and everyone poo-poos the idea, not sure whether undersize bearings are easy to get.
__________________
Okeanos is offline   Reply With Quote
Old 03 August 2008, 12:59   #10
Member
 
Country: UK - England
Town: Falmouth.
Boat name: Stingray.
Make: Predator.
Length: 6m +
Engine: Out, petrol, 2x90hp.
Join Date: Mar 2008
Posts: 36
Quote:
Originally Posted by Simon B View Post
Did they make to F100 in large numbers? I'd heard it was discontinued and replaced by a commercial version F90, do not know if this power head is the same though.
They still make the F100, they have been for over 7 years. Never seen nor heard of an F90!

http://www.yamaha-motor.co.uk/produc...s/four_stroke/
__________________

__________________
Okeanos 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 03:36.


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