Riding Mowers & Tractors: Leaking oil or gas

Check the oil level when the engine leaks oil. Drain oil to the full mark on the dipstick if you find the engine overfilled. A leaking head gasket or sump gasket can also cause oil leaks. Replace any damaged engine gaskets. If you notice gasoline stains on the pavement or garage floor, investigate the source of the leaking fuel. Rebuild or replace the carburetor if it leaks gas. Check the fuel pump for leaks and replace the pump if it's damaged.

riding mowers & tractors

These repairs may help solve your riding mowers & tractors problem

Replace the riding mower carburetor assembly

Replace the riding mower carburetor assembly

The carburetor mixes gas with air before the fuel goes into the cylinder. If the gas/air mix isn't balanced, the engine won't start or the engine will run rough and stall when you try to drive the riding mower. A damaged carburetor may also leak gas. Replace the carburetor if it causes any of these symptoms.

January 1, 2015
By Lyle Weischwill
How to replace a riding lawn mower carburetor

When a lawn tractor engine surges or is hard to start, the problem could be a clogged or damaged carburetor. This DIY repair guide and video show how you can replace the carburetor yourself.

Repair difficulty
Time required
 45 minutes or less
Read more
Rebuild the riding mower engine carburetor

Rebuild the riding mower engine carburetor

The carburetor mixes fuel with air to create a combustible mixture that enters the engine cylinder and ignites to drive the piston. Impurities in gasoline can clog the carburetor, preventing the engine from starting. Carburetor clogs can also cause the engine to run rough and the engine may stall when you try to drive the riding mower. Seals and gaskets in the carburetor eventually wear out and can leak gas. Use a carburetor rebuild kit to refurbish a clogged or leaking carburetor.

January 1, 2015
By Lyle Weischwill
How to rebuild a riding lawn mower carburetor

Does your riding lawn mower engine run rough or misfire? The carburetor might be clogged or worn. This DIY repair guide and video show how to rebuild the carburetor in a riding lawn mower in about an hour.

Repair difficulty
Time required
 60 minutes or less
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Replace the riding mower head gasket

Replace the riding mower head gasket

If you notice an oil leak and your mower's engine can't reach normal operating speed or the mower struggles to climb a hill, the engine may have blown the head gasket. The head gasket seals the cylinder head to the top of the engine. Air leaking past a damaged head gasket reduces cylinder compression causing a loss of power. A blown head gasket leaks oil because the gasket doesn't seal the cylinder head mounting surfaces. Replace the head gasket if it leaks.

Replace the riding mower fuel pump

Replace the riding mower fuel pump

The fuel pump moves fuel to the engine from the fuel tank on the riding mower or lawn tractor fuel tank. If the engine won't start or quits after starting, the fuel pump might not be working. A cracked fuel pump leaks gasoline. Replace the fuel pump if it leaks or doesn't pump fuel to the carburetor.

Symptoms common to all riding mowers & tractors

Choose a symptom to see related riding mower and lawn tractor repairs.

Main causes: worn or broken ground drive belt, bad seat switch, transaxle freewheel control engaged, transaxle failure, dirty carburetor
Main causes: dead battery, stale fuel, bad starter solenoid, ignition system problem, bad ignition interlock switch, clogged carburetor
Main causes: damaged cutting blade, worn deck pulley, damaged mandrel pulley, loose fasteners on mower deck components
Main causes: engine overfilled with oil, leaky head gasket or sump gasket, damaged carburetor seals, cracked fuel pump, broken fuel line
Main causes: punctured tire or inner tube, leaky valve stem, damaged wheel rim
Main causes: unlevel mower deck, dull or damaged cutting blades, worn mandrel pulleys, bent mower deck, engine needs tune up
Main causes: damaged tie rods, bent or worn wheel spindle, worn front axle, damaged sector gear assembly
Main causes: worn or broken blade belt, broken belt idler pulley, blade clutch cable failure, bad PTO switch, damaged mandrel pulleys
Main causes: shift lever needs adjustment, neutral control needs adjustment

Repair guides common to all riding mowers & tractors

These step-by-step repair guides will help you safely fix what’s broken on your riding mower or lawn tractor.

How to replace the starter motor on a riding lawn mower

If you hear the solenoid click but don’t hear the starter motor spin when you turn the key, follow these steps to replace it.

Repair difficulty
Time required
 30 minutes or less
January 1, 2015
By Lyle Weischwill
How to replace a riding lawn mower spark plug

If the engine is hard to start or if the spark plug electrode is burnt or cracked, take 15 minutes to replace it.

Repair difficulty
Time required
 15 minutes or less
January 1, 2015
By Lyle Weischwill
How to replace a riding lawn mower carburetor

If the engine of your lawn tractor surges or is hard to start, the carburetor could be the problem. Follow these steps to install a new one.

Repair difficulty
Time required
 45 minutes or less

Articles and videos common to all riding mowers & tractors

Use the advice and tips in these articles and videos to get the most out of your riding mower or lawn tractor.

May 1, 2017

Riding lawn mower engine spins but won't start video

By Sears PartsDirect staff

Troubleshoot fuel, spark and compression issues.

June 1, 2016

How to mow a lawn for healthier grass

By Erin Hynes

How often and tall you mow your lawn has a big impact on its health. Check out these 3 rules.

March 1, 2016

How to change the Smart Switch Ignition password on a lawn tractor video

By Sears PartsDirect staff

See how to unlock the factory default start code so you can set your own passcode.