Not only can a lawn mower blow blue smoke if there is a problem, but a lawn mower can also blow grey smoke.
There are a few causes of grey smoke in a lawn mower. A broken head gasket can cause both blue and grey smoke to cloud the area around your lawn mower.
Another cause of grey smoke is a rupture in the breathing tube. This tube allows air to go from the combustion chamber to the exhaust, allowing air to have proper circulation within your lawn mower. If this tube is broken, then your lawn mower won’t be able to keep a proper circulation of air which means pollution will be built up and spill out as grey smoke.