Mercury 40 4hp GNAT issues
Trying to sell an old 1980's mercury 40 4HP GNAT 2 stroke outboard engine that has not been run for the last 20-30 years. I can get the engine to run after a number of pulls however it wont run on idle and keeps cutting out after 30-1min. You can keep the engine running longer if you rev when its about to cut out but putting to idle cuts out. Also turning the choke doesn't seem to allow the engine to start and cuts it off.
Ive replaced all the fuel lines and fuel filter. Also pulled the carb off twice and cleaned all the part with a spray carb cleaner and cant see any muck less in there. I have also tried topping the fuel tank up to the top and running without the cap on with no luck.
Im using old 7-8 year old 2 stoke oil but new petrol in it. Is it worth trying new 2 stroke oil and is there anything else to try? Getting bit lost for options of what to check next
Thanks for any help