Hmmmm - fuel filter - that may answer the next problem. Turned out I had the wrong "diaphragm" installed. I used an identical piece that didn't have flaps in the holes - duh! .
Started up OK so put it away till last weekend when I got stuck into some serious trimming. Ran great for an hour then gradually lost power - kept adjusting till it eventually died and now won't start. So guess the fuel filter needs a look see.
