Honda G150 surging/ hunting especially under load
So I've been using the wolesley merry tiller I picked up which was fitted with a honda G150 engine.
I gave it a once over when I first got it - changed the oil (SAE 10w40 since I had it), changed the air filter, cleaned the plug and gave the carb a blow through with some brake clean, checked the governor adjustment and off we went.
It was running great for a few hours but today after about half hour running it started to surge like the governor was pulling and pushing and not sure what to do.
Checked it had fuel and that it was coming out of the tank, checked the plug and boot, gave the carb the obligatory tappy tap to check float wasn't stuck. Tried letting it cool off a little, adjusted the governor again to see it hadn't slipped.
Nothing really seems to have helped, part of me wonders whether it may be the governor assembly itself having a paddy. I did note the shaft had a lot of end play - 5-6mm of endplay in the governor shaft.
Without blindly diving into replacing the governor is there anything else I could try? Going to try giving the carb another blow through and add fresh fuel tomorrow but after that I'm at a loss.