Honda Rotary Mower

[Khandro]

Ran faultlessly for many years, but starting it up for the new season, it starts, runs for a few seconds and dies.
I've drained out the petrol tank and carburettor, replaced it with fresh super petrol, washed and cleaned the filter and re-oiled it, cleaned the spark plug and checked the gap, and checked the oil, all to no avail, any ideas please?

[Bertrum]

The problem is most likely to be in the carburettor, a blocked jet would be my guess

[SlackAlice]

I'd agree with Bertrum, pay particular attention to the 'float' valve. If you do need to clear a jet use an air compressor/pump rather than poke it through with a piece of wire. ☺☺

[TWR]

You have primed the unit I take it? these petrol mowers when left for a while can be a pig to restart, just check the small inflow fuel pipe, has it perished & caused a fuel line blockage?

[Khandro]

Thanks guys. The problem was definitely in the fuel supply, probably water in the carburettor. After doing all the above, - draining the tank and carburettor - when I posted I had only made two attempts at a re-start, I should have continued, because an hour later, demonstrating the problem to my neighbour it ran perfectly. I assume that there was still some water in the jet which cleared completely by the passage of the new clean petrol.

[DocHH]

Petrol is not what it used to be, if left for a long period it will gel. That would cause a blocked jet. I was advised that at the end of the mowing season to turn the petrol supply off, then run the engine until it stops, so it has no petrol at all in the carburettor. The at the start of the new season put new petrol in with what was left in the tank.

[Khandro]

Doc; looking for the plug type my wife produced the manual (she keeps everything) and what you say is exactly what it tells you to do each winter, - which proves the old adage, 'when all else fails, read the instructions.
It's now running fine.