I use 'chemtech' 'shock treatment' degreaser. Buy a 20L container for about $60. Mix it 1:1 with water in a 2L spray bottle from bunnings and use that to wash mowers. Use care, its corrosive class 8, stings on sensative skin and eyes and stuff.
It does a good job, An old tooth brush for the stubborn stuff. Some mowers you have to wash more than once, wash it with the engine cover on, then engine cover off.
Will tarnish bare aluminium. Will also strip off some paints. Bad resprays with bad paints and i had one gold low arch thats paint didnt fair too well.
Gets grime off wheels and the like. Need to use the brush to help with grime around the lower edge of the frame and also the oily greasy thick stuff.
Ive only got hose pressure, if you had a pressure washer it would do an even better job.
Got a gravel front yard, i wouldnt go washing with the stuff on the lawn even though its biodegradeable according to the lable.
Also use the same stuff to wash out foam filters. A bit of hot water in a bucket a bit of degreaser and squish away. gets them clean, even the ones where the mower has been tipped upside down and the filter full of engine oil.
Also wash up plastic covers and air filter housings in the laundry trough with it.
