What does a ticking noise in my lawn mower indicate?

Does this happen at idle or full speed?If at full speed It is doubt-full that it is engine related, as the engine would be revolving at about 1800 rpm ( at that rpm the noise would disappear). If at idle, it could be valves tapping- a loose plug-a connecting rod bearing - a crank bearing - or a loose flywheel. And of course is it happens when pushing, it may be a wheel noise...

Check the deck /blade gap - if the deck bent in, it could cause that ( if you ran into something) if you didnt, it could be the flywheel screen touching the metal flywheel shoud. Rotate it by hand when its off and cold and see. If thats not it, when was the last time the oil was changed? If its not, its possible one day youll be mowing, until the rod/piston comes out the side. The ticking can be the crank bering going bad, something slowly comming apart inside. Its hard to tell w/o hearing it.

Kidd

sounds like the blade is hitting the side of the deck,

hence ticking,

Remove the spark plug wire before checking this, by turning the blade, it can start up if the plug wire isnt removed,

if its a light tick it will get worse as the deck viberates

It could be as simple as a loose blade, or as complicated as a bad connecting rod! Hard to tell without hearing it.

This is open to discussion and there are in fact several possible answers to the question...

oil

You had any radical islamofascists stop by your garage recently?

dunno