I have just acquired a ATCO cylinder petrol lawn mower from my gran's cellar. I have drained the tanks and cleaned the carb, put a new plug in it and it still does not start. I have mechanical experience but I need some help on this one there is fuel air but no spark PLEASE HELP!!!
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You may need to adjust the gap on the spark plug?
Is the plug lead/cap well connected?
Check the gap on the sparkplug. I had trouble with my mower, and found a clogged air filter. If you haven’t try replacing that.
You do not say how you determined that there was no spark, but if you have mechanical experience then you obviously know that you have to have the spark plug touching the lawn mower case (best place is away from the hole, but touching that part of the case). I do not know if you are aware that some mowers need to be primed before starting. That is usually a rubber piece on the front, you need to cover the hole and press it in, release and then press in again. My mower manual says three times, but in cooler weather, I need to press five times. When it is cold out, and I stop the mower before it has warmed up enough or sat long enough to cool down, I have to prime it the three times again. The last possiblility is that there is an electronic device to provide sufficient voltage to create a spark across the spark plug and that may be defective.
If it hasn’t run for a while the compression could be poor.. These old mowers could be very tempremental.
Sometimes heating the plug helps.