that was one of the first things i did, my first thought was maybe the float was being held up, in the closed position, by the bowl after i had re-assembled it so i popped the bowl off and checked the flow by raising the float up and down. there
is no problem with the petrol flow as there is a constant stream...
it always runs for the same short period before dying, a few seconds, to me the nature of the run/stop time suggests it's a fuel issue, but i have checked the usual causes and nothing is obviously wrong. which s why i posted in case there was some magical mower thing but i am just being optimistic