Have a look at http://www.mowerfix.info/Problem_Solving_Guides/HONDA%20ENGINES%20SELFHELP%20GUIDE%202009%20Issue%202,0.pdf I found it very helpfull. Have the same prob with my mower so I figured it was a fueling prob. Left out side over winter with fuel in? not a good idea!.
1; unplug the HT from spark plug
2; Drain down all the old fuel out of the system 100%. you need a 10mm ring spanner, drain down at the bottom of the carb(nut at the slight angle). Close up the nut taking care not to over tighten.
Give the engine a good 10 pulls to clear the carb.
3; refill with new unleaded.
4; re connect the HT and turn the fuel tap back on and away you should go. May take a few pulls to get things going. Try this first and if it does not work there are other things that may need to be done like removing the carb and cleaning the float needle to checking the auto choke.
K Rado, April 2010
