All engine's should start on demand,Reading u'r msg it seems that u do get it running,so making assumptions,U seem to have a fault in the ignition HT system.HT is most loaded at start up,and u seem to have plug/cap/lead breakdown,or any combination.But,start with cheap things.Check all tappet clearances and adjust if neccesary,especially exhaust valves(backfire)If all ok,then renew and gap all plugs.If no change then plug caps are next suspect.I would suspect that u have at least 2 tight exhaust tappets,1-2 fouled plugs and maybe 1 faulty plug caps.Follow this.Cold day,damp,heavy load on ignition system.fuel unnable to ignite and passes into exhaust,faulty plug/cap fires,starts,missfires,hot gasses flow to exhaust and ignite unburnt fuel,backfire.Good plug voltages are 3-5 kilavolts,missfire can produce 20 kilavolts.more than enough to go down pipes.All this supposes that it runs ok on warm dry days.But first GET YOUR VALVE CLEARENCES checked.
caine, August 2008
