Weekend Margin

Load tells you which circuit it is running on. It is the most useful free test on any small engine.

Almost always, and specifically the idle circuit rather than the main jet. Under load the engine draws through the main jet and everything is fine, which is exactly what you are seeing. At no load it is running on the pilot circuit, and that passage is far smaller and blocks far more easily.

Pull the bowl, remove the pilot jet if yours is removable, and clean it and the small passages around the throttle plate. On many of these the pilot is pressed in and you clean it in place with cleaner and air.

The other candidate is the governor. If cleaning does not settle it, check the linkage for slop and the spring for being stretched or hooked in the wrong hole - a worn linkage hunts because the governor overshoots both ways. But do the carburettor first, given the winter sit.

I reset a 2000 card backlog once because a forum post told me to. I lost every interval I had built over eight months and spent the next three re-learning cards I already knew. It felt great for one evening and bad for a season.

Also check whether the door has been repainted four times. Layers add up and behave exactly like swelling.

Then it is not the exhaust. Clean the screen anyway while it is apart and go and look at that flywheel key.

Half the diagnosis on these is remembering what you did to it last year.

Check the exhaust port and the spark arrestor screen too. A carbon blocked muffler will stop a two stroke firing, and on a six year old trimmer that has run rich it is common.

Check the excess as well. A £250 excess against a £2,000 total contents value means a lot of realistic claims aren't worth making.

Whichever you choose, stick with it for six months. Changing wax means all your wick testing starts again from zero.

This is what I would do, but only because I enjoy it. If the evening is precious, buy the carb.