to rich of a gas mixture
If its black smoke you are burning oil possibly due to oil getting in your exhaust by tilting the lawnmower on its side or your rings are allowing oil by.
burning oil
Doesn't matter what type of vehicle, this indicates an exhaust leak and an oil leak. The burnt oil and the exhaust, get pulled into the cowl which is where the air for the interior comes from! Not very healthy...
cause so times if you crash in a rock or a tree . then the oil comes out of the pipe
Serious trouble. It usually means a broken oil (piston) ring. Another possibility is that your exhaust valve seals are bad/gone or valve guide is worn in excess. Another possibility is it is condensation coming out of exhaust mixed with black residue from exhaust and only looks like oil.
You probably have a bad turbo.
Your in a high condensation area and it has collected in your exhaust system and causes old mufflers and exhaust system to rust.
When a weird noise comes from the exhaust after stepping on the gas pedal, it could mean that there is a hole in the exhaust pipe. Sometimes the exhaust pipe will rust and need to be replaced.
You may have oil on the exhaust, once this has burnt off the smoke should stop.
Overheated, exhaust leak, oil leak on manifold-hard to speculate
It's carbon and unburned oil that you put in the gas mix. Using a gas mix with less oil will eliminate some of the unburned oil that comes out the exhaust but you need to be careful you do not run the engine with not enough oil in the gas as that is the oil that the engine needs for its lubrication.
It is possible there is a baad oil leak on the exhaust. Have it checked out. Good luckJoe