Troubleshooting for Lawn Tractor Problems: Rattling Sounds

Loose Blades

• The mowing deck of your lawn tractor contains sharp blades for cutting grass and, in some cases, mulching. These fast spinning blades can work loose over time with normal use. Check the blades if you hear rattling. Turn off the mower and see if they feel loose and then look for any bolts that may need tightening. If the blades are excessively dirty or bent by a rock, stump or other object, that could cause the rattling sound as well. Clean the blades thoroughly and replace them if they have been damaged.

Fuel Octane

• Within the engine’s combustion chamber the pistons can collide with the carbon buildup and create a knocking noise that may be interpreted as a rattle when the engine is revved up. One reason the engine gets to this point is an inferior fuel type. Make sure you are using fuel that has a suitable octane rating. Check your tractor’s owner’s manual to find out what kind of fuel is recommended and stick to the recommendations for best performance and a quieter engine. Cleaning the cylinder heads may also be necessary to stop the noise.

Oil Problems

• The lifters and valves within the lawn tractor’s engine need good lubrication. Motor oil provides this lubrication, and if it the wrong viscosity, or is too old or at a low level, the lifters and valves will not be lubricated properly. Putting clean, fresh oil in the engine may be enough to stop the associated ticking and rattling sound. Sometimes it may require more effort and the motor may need to be disassembled, cleaned and rebuilt.

Clutch

• You tractor has a clutch for pressing when you change gears and problems with it can cause a rattling noise. Overheating, or a loosely mounted clutch, can make the clutch bearing fail, which will produce a rattling sound during running. The clutch’s adapter plate may also collide with the anti-rotation pin while the tractor runs. This normal movement can cause a rattle. Insulating the pin with rubber can muffle excessive rattling.