Hi MF,
How did you go with the fresh fuel? Out of curiosity, what type of fuel and brand of 2-stroke oil do you use?
The thing that confuses me is that it works when the spark plug dries and excess fuel is expelled through the spark plug hole. Which would suggest that there's too much fuel in there in the first place, completely soaking the plug. We know removing excess fuel resolved the issue, so to me, the first logical step is to try to replicate that without removing the spark plug. If the tap is working (Simple test), try turning off the tap a little before switching off the mower to reduce the mix in the carby/engine, and see if that resolves the issue. The best way to do this would be to turn off the fuel tap and use a torch to look into the carby bowl. Once the fuel level drops right down you can switch off the mower. Alternatively, and I wouldn't ever recommend this for continual use, but you could just turn off the tap and let the engine run dry (Not a recommended option). If doing that resolves the issue, then you can start looking at things in-between. The carby to me would be the most logical place, if the needle isn't seating correctly coupled with the fuel being left on between stopping and starting (Which is entirely normal), the engine could be flooding.
Have you noticed excess fuel use?
Cheers,
pau13z
