Due to work commitments and not enough "play time" the Johnson 15hp is not going to be used for at least a month.
I understand that I need to drain of the 2 stoke mixed fuel in the carb. Is it worth flushing it out with anything to make sure it's really clean?
I never bother flushing. If you drain it by shutting off / disconnecting the fuel & running the engine 'till it dies that will work fine. Pulling choke out & try to restart it will get anything out that's going to be a problem.
Flushing would only really be sensible with neat petrol, but that may cause lubrication issues when you want to restart it later!
If your tank has a double quick connector, disconnect from tank rather than from engine and ran engine following 9D280 advise, will have free guarded old fuel on gas line. Engine will start much faster on next outting.
