Why Does My John Deere Riding Mower Smoke?

Dirty Air Filter

• Like any combustion engine, your John Deere mower’s engine needs to breathe. It pulls air in through a filter to get the air it needs to run smoothly and efficiently. If the air filter is dirty, it can have some problems. It can run rough and with poor fuel efficiency. It may even stall out completely or overheat. The dirty air filter may also cause the mower to billow out black smoke, which is especially common if the air filter is oil soaked, also indicating a gasket problem in the engine, causing oil to blow through the filter.

Breaking It in

• Some smoke is associated with a John Deere riding mower is completely normal. The engines on these mowers require some break-in time. Usually several hours of use is required before the engine is completely broken in. Until that time comes, John Deere’s product manuals indicate that white or blue smoke is a common sight. John Deere also recommends the use of specially-formulated break-in oil during the first 100 hours of operation.

Oil Spill

• If you notice some smoke rising from the engine area shortly after oil has been added to the mower, the smoke will likely go away soon. Missing the mark while pouring oil into the proper place on the mower is easy, and some could spill out on the engine itself or the surrounding parts. When the mower runs, these parts get hot and the oil will burn off, resulting in some black smoke and an odor. After the oil burns off, the smoke will stop.

Air-Fuel Mixture or Carburetor

• When you have black smoke coming from the exhaust of your mower and you have already checked the air filter and determined it was in good condition, you have to assume the issue is a fuel-air mixture problem. The engine is getting too much fuel for the air it is receiving. It is the same basic problem as a clogged air filter, only it may relate to the choke. Ensure you have the choke opened up all the way, which should help with the smoking problem. If not, you may have a faulty carburetor and will need a small engine repair specialist to take a look.