Thanks for input guys but just to clarify:
1. Engine is minty and fully serviced to the letter by me after purchase it and it ran perfectly on two fairly long sea days throughout after this (new NGK plugs, gear oil, fuel system/tank clean, gear oil, impellor etc, etc). Only done about 8 - 10 hrs since the service then.
2. No issues with fuel line, bulb, vent etc - as I say it runs fine with throttle held open (conclusion that non-idle circuit fuel suply and plugs etc cannot be an issue) just will not start without throttle held open or idle. Very on/off - ie it won't even cough or splutter/start on idle.
3. After last sea day it was fine when flushing.
Odd thing is coming back three weeks later you might expect it to cough splutter or run erratically but as above it just will not run full stop - leads me to believe it must have gummed up in the idle jet or something despite running dry and stabaliser? ie nothing has 'broken' just sitting there?
As I say fuel was decent with stabaliser added right away.
Anyone stripped one of the carbs in these and can help out with clues - has to be a carb issue surely.
Coming across as Mr Grumpy but 100% totally pi$$ed off with this - boat engines are now in my experience so unreliable if despite all the above (ie looking after them perfectly) they still let you down in this way just because they have sat there for three weeks. And after the first time it lets you down you never have the same confidence again especially when going to sea...
Originally Posted by uncle al
It sounds like fuel trouble, will it tick over and run ok if pressure is kept on the primer bulb? If it does I would want to fit a fuel pump repair kit,if it doesnt see some suggestions below.
1/ is it old stale fuel?
if so remove strip clean the carbureter re-assemble and refit.
2/ has it been serviced recently?
Yes, see above.
3/ are the correct spark plugs fitted as per parts book?
4/ is the obm set up correctly as per chapter on settings for timing and carburation?
5/ are the compressions ok?
4+5 - not checked other than idle speed but ran perfectly for 8 hours or so before 'laying up' (!) for three weeks.