Reply
 
Thread Tools Search this Thread
 
Old 30 July 2020, 10:05   #1
Member
 
Country: UK - England
Town: Cheddleton
Boat name: Black Hawk III
Make: Osprey
Length: 7m +
Engine: 300
Join Date: Aug 2016
Posts: 50
Yamaha 25HP - 2 stroke - tickover problem

My 2004 Yamaha starts first pull and runs nicely with a bit of revs, but doesn't want to tickover, if the twist throttle drops anywhere below what appears to be the choke position on the throttle (pic attached).

The engine needs a service, but any ideas as to what might be the issue?

Thanks. David
Attached Thumbnails
Click image for larger version

Name:	Throttle.jpg
Views:	26
Size:	118.1 KB
ID:	134442  
__________________

__________________
Vipermax80 is offline   Reply With Quote
Old 30 July 2020, 13:22   #2
Member
 
A1an's Avatar
 
Country: UK - Scotland
Town: Fort William
Make: Humber Destroyer
Length: 5m +
Engine: Yamaha F80
Join Date: Mar 2012
Posts: 2,435
RIBase
I'd start with a carb clean. Did this symptom appear after storage of the engine?
__________________

__________________
There is a place on this planet for all of Gods creatures.........right next to my tatties and gravy.
A1an is offline   Reply With Quote
Old 30 July 2020, 16:24   #3
Member
 
Country: UK - England
Town: Cheddleton
Boat name: Black Hawk III
Make: Osprey
Length: 7m +
Engine: 300
Join Date: Aug 2016
Posts: 50
Yes been in storage for a good while.
__________________
Vipermax80 is offline   Reply With Quote
Old 31 July 2020, 01:28   #4
Member
 
A1an's Avatar
 
Country: UK - Scotland
Town: Fort William
Make: Humber Destroyer
Length: 5m +
Engine: Yamaha F80
Join Date: Mar 2012
Posts: 2,435
RIBase
My guess is it's been left will fuel in the carb, this evaporates and can sometimes gum up the tiny holes in carb jets.
__________________
There is a place on this planet for all of Gods creatures.........right next to my tatties and gravy.
A1an is offline   Reply With Quote
Old 31 July 2020, 04:00   #5
Member
 
Country: UK - England
Town: East Anglia
Boat name: Nimrod II
Make: Aerotec 380
Length: 3m +
Engine: Yamaha 15Hp 2-stroke
Join Date: Nov 2007
Posts: 5,584
My action to try and resolve would depend on how it's behaving. Badly blocked idle jets will often mean a motor will only start with the throttle quite a way open and the moment you wind back to anything like the idle position they will stall almost as if switched off.

Is it doing that or starting OK just over idle and then misfiring a bit for quite a few a few seconds before finally stopping?

If the latter I'd try raising the idle speed screw/s a bit to see if it will keep running at idle with a modest adjustment. It is just possible if it were put away at the very lower limit of its idle speed range it needs that bit of increase until it's run for a while is all it needs.

Is it running on the fuel left in storage?
__________________
Fenlander is online now   Reply With Quote
Old 31 July 2020, 07:37   #6
Member
 
Country: UK - England
Town: Cheddleton
Boat name: Black Hawk III
Make: Osprey
Length: 7m +
Engine: 300
Join Date: Aug 2016
Posts: 50
Fresh fuel being used. But the engine has not be running for long, only on a stand and muffs.

Another pic of the hand throttle attached, will continue to run nicely when the two arrows are aligned i.e. will seem to run indefinitely and not die, when revving the engine harder, you do get the odd cough, but again the engine keeps going, doesn't die. Its only when you twist the throttle further back into what I am assuming is the tick over position, then the engine virtually cuts out straight away (bit like pulling the kill core).
Attached Thumbnails
Click image for larger version

Name:	Engine Throttle 2.jpg
Views:	16
Size:	82.5 KB
ID:	134445  
__________________

__________________
Vipermax80 is offline   Reply With Quote
Reply

Tags
yamaha

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




All times are GMT -5. The time now is 03:53.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.