What does a lawn mower tune up consist of?

Keeping your lawn mower properly tuned up is essential for optimal performance and longevity. A tune up involves inspecting, cleaning, adjusting, and replacing worn parts as needed. Here is a detailed overview of what a complete lawn mower tune up entails:

Change the Oil

One of the most important parts of a tune up is changing the oil. Over time, engine oil becomes contaminated with dirt, debris, and metal shavings, which can cause excessive wear on internal components. Old oil also loses its lubricating properties. Here are the steps for changing mower oil:

• Run the mower for a few minutes to warm up the oil so it drains smoothly.
• Disconnect the spark plug wire.
• Clean the area around the oil fill/drain plugs to prevent debris falling in.
• Place a pan under the drain plug.
• Remove the drain plug and allow the dirty oil to completely drain out.
• Replace the drain plug when finished.
• Carefully pour fresh oil into the fill tube until it reaches the “Full” line on the dipstick.
• Replace the oil fill cap.
• Reconnect the spark plug wire when finished.

Be sure to use the type and quantity of oil specified by the mower’s manufacturer. Properly disposing of used oil is also important for environmental safety.

Inspect and Replace the Air Filter

The air filter prevents debris and dirt from entering the engine’s internals. A clogged filter restricts proper airflow, potentially causing performance issues. Follow these steps to service the air filter during a tune up:

• Locate the air filter housing on the engine.
• Release the clips or screws holding on the air filter cover.
• Remove the foam or paper filter element.
• Inspect it for excessive dirt buildup or damage.
• Tap it gently on a hard surface to remove loose debris.
• If it’s excessively dirty, replace it with a new filter.
• Reinstall the cleaned or new filter in its housing.
• Replace the air filter cover and secure it.

Replacing a dirty air filter helps keep the engine running smoothly and can improve gas mileage.

Inspect the Spark Plug

The spark plug is crucial for igniting the fuel in the engine to generate power. Here are the steps for inspecting and potentially replacing the spark plug during a mower tune up:

• Disconnect the spark plug wire for safety.
• Use a spark plug wrench to remove the old plug.
• Inspect the electrode at the base of the plug – it should not be excessively worn.
• Check for heavy carbon deposits or oil fouling that can inhibit spark.
• Use a wire brush to gently clean carbon off the electrode and housing if needed.
• Check the spark plug gap with a feeler gauge – it should be around 0.030 inches typically.
• If the electrode is worn, excessive fouling/deposits are present, or the gap is out of spec, install a new plug.
• Install the plug by hand until tight, then use the wrench for final tightening.
• Reattach the spark plug wire when finished.

Fresh spark plugs enhance cold starting, smooth operation, and engine power output.

Inspect Fuel System Components

It’s important to inspect the various parts of the fuel system during tuning. Follow these steps:

• Fuel Filter – Locate inline fuel filter and check for debris buildup. Replace if clogged.
• Fuel Lines – Inspect for cracks or leaks. Ensure fittings are tight.
• Carburetor – If equipped, remove air filter housing and inspect carburetor for dirt buildup. Clean with carburetor cleaner and brush if needed.
• Fuel Pumps – Check for leaks or abnormalities. Test operation.

Proper fuel delivery is critical for engine operation. Fixing any identified fuel system issues will restore smooth performance.

Sharpen or Replace Mower Blades

Dull mower blades result in ragged, uneven cutting. Sharpening or replacing the blades is one of the best ways to restore a smooth cut. Here’s how to address the blades during a tune up:

• Disconnect the spark plug wire.
• Wearing thick gloves, remove each blade by loosening the blade bolt.
• Inspect each blade carefully for significant wear, nicks, bent areas or other damage.
• If a blade is damaged beyond repair, replace it with a new one.
• Use a sharpening tool or hand file to restore a sharp edge on each blade if they are in good overall condition.
• Balance the blades using a small bubble level to check that they sit flat horizontally.
• Reinstall the sharpened or new blades, tightening the mounting bolts to the specified torque.

Sharp blades require less power to operate the mower and make for healthier grass growth.

Inspect and Tighten Loose Fasteners

Vibration from mower operation can loosen nuts, bolts, and screws over time. It’s wise to inspect and tighten any loose fasteners when doing a tune up. Here are some key areas to check:

• Engine mounting bolts
• Blade mounting bolts
• Wheel and tire hardware
• Handlebar attachments
• Engine cowling/shrouding screws
• Safety shields

Tightening loose fasteners reduces noise, potential damage from components rattling around, and safety issues.

Inspect Belts

Most mowers have at least one belt responsible for linking engine pulleys to operate the blades or self-propel drive. Follow these steps when inspecting belts:

• Remove any protective belt covers/shields.
• Look for cracked, frayed, or otherwise damaged belts.
• Check for adequate tension when depressing the belt – there should be just a bit of give.
• Replace any worn or damaged belts with new ones of the correct size.
• Double check pulley alignment if replacing a belt.

Proper belt condition is imperative for safe blade operation and drive function.

Lubricate Moving Parts

Lubricating movable joints, bearings, and linkages reduces friction and wear. Here are some mower components that may need lubrication:

• Wheel bearings and bushings
• Pivot points on deck and cutting height adjusters
• Handlebar hinges
• Throttle and blade control cables
• Electric clutch components, if equipped
• Drive control linkages on self-propelled models

Use light oil or spray lubricant made specifically for lawn mowers. Grease fittings should be greased with ordinary grease. This prevents binding and squeaking while enhancing the mower’s longevity.

Inspect Mower Deck

The mower deck houses the cutting blades and spin pulleys. Here are key things to inspect on the deck:

• Ensure the deck is clear of grass buildup underneath.
• Check for bent or damaged areas, especially around blade housings.
• Ensure smooth deck operation when raising/lowering.
• Listen for odd noises that could indicate problems.
• Verify blade pulley spins freely.
• Check belt keepers/guides under the deck.

Addressing any deck issues now prevents potentially bigger problems down the road.

Inspect Wheels and Tires

It’s important to check the condition of the wheels and tires during tuning. Follow these guidelines:

• Look for adequate tread depth – replace tires if worn.
• Ensure tires are properly inflated.
• Check for damage or cracks.
• Remove small debris like pebbles or shards lodged in the tread.
• Ensure wheel bolts are tight.
• Confirm wheels spin freely without wobbling.
• Inspect caster wheels for free swiveling motion.

Proper wheel and tire condition impacts mowing performance plus safety for the operator.

Check Safety Features

Lawn mowers are equipped with important safety mechanisms. Inspect their operation during a tune up:

• Blade Brake – With the engine running, release the blade control. Listen for the blades to stop within 3-5 seconds.
• Operator Presence Controls – With the blades spinning, let up on the handles. The engine should cut off.
• Guards – Ensure all protective shrouds and guards are in place and in good condition.
• Warning Decals – Check for readable safety labels. Replace any that are missing or severely faded.

Confirming the proper operation of safety features helps prevent accidents and injuries while mowing.

Check for Leaks

It’s wise to check for fluid leaks during a complete tune up. Look for signs of oily drips or spots around these areas:

• Around the oil drain plug
• Near gearbox breather vents
• Around wheel rims
• Under the engine and gasoline tank
• At belt pulleys
• Near hoses, clamps, and fittings

Identifying and repairing leaks now prevents staining concrete in your garage plus potential damage or hazards from low fluid levels.

Clean Engine Exterior and Cooling Fins

Removing debris buildup on the engine exterior is important for proper air circulation. Follow these tips:

• Use compressed air to blow off dust and dirt.
• Use a soft bristle brush if compressed air alone doesn’t remove grime.
• Clean any caked-on mud with a plastic scraper.
• Wipe down the surfaces with a clean shop rag.
• Remove grass clippings and debris wrapped around engine cooling fins.

Keeping the engine exterior clean facilitates proper air flow for cooling purposes.

Test Operational Performance

The final step is to test overall mower operation after completing the tune up. Here is what to check:

• Start the engine – it should turn over smoothly and start easily.
• Listen for odd noises or vibrations that could indicate problems.
• Allow engine to fully warm up and note any performance issues.
• Check blade operation by engaging the deck – listen for smooth spinning.
• For self-propelled – verify appropriate speed and smooth engagement.
• Make any final adjustments or repairs needed.

Addressing any lingering performance issues ensures your mower is ready for the season following your tune up.

Conclusion

Performing routine lawn mower tune ups following the steps outlined here will keep your mower running reliably all season long. Investing a little time in preventative maintenance prevents headaches later on through better performance, fewer unexpected breakdowns, and extended machine life.