Norm, easiest way is to put you prices up. They see your prices are too cheap and those type will try to take advantage.
They won't understand don't come back - having to pay more will keep them away
When the undesirables rock up with their crap, tell them its worth $10 trade in on a mower. Work out a slightly staggered price list eg
Chonda 16in $90
Chonda 18in $100
Briggs 18in $120
Victa 2 stroke $120
Post in the ad a couple photos - 1 of painting or welding the deck so it is clear the work that has gone into it even just keep a generic green deck and grey deck photo - those seem to be your most common colours and saves effort of taking a different photo each time
Show you have not simply picked up a mower on the curb, sprayed carby clean down it and put it up for sale. Unlike most mower repairers (myself included) you have thoroughly sorted out the deck as well.
The deadbeats will get the cheap chondas and you get better quality customers buy the quality ones (who won't straight fuel)
Those who are reasonable know that $120 for a Victa 2 stroke that has has the deck welded, painted, carby reworked and fully serviced will know they are getting a good deal.
Look through gumtree with a 10km radius - you won't find a mower reseller in the area under $100, and or a mower with briggs or PT for pretty much under $120.
Also put at the beginning of the ad 'Don't bother with lowballs' or similar (which you do anyway)
those who are genuine don't mind and those who are timewasters will look elsewhere
