How to Service a Cub Cadet Riding Lawn Mower: Step-By-Step

To protect your investment, keep your Cub Cadet riding mower operating at its best by regularly servicing it. Skipping regular maintenance of your mower can cause damage to your engine, fuel, and electrical system.

Many significant problems can be caught early and prevented by regularly servicing and checking your mower.

A full service on a Cub Cadet riding mower includes an engine oil and filter change; checking the fuel system for leaks; inspecting components for wear or damage; scraping the mower deck; sharpening mower blades; replacing filters; and lubricating the mower.

I have put together a complete list of Cub Cadet items and steps required to service your mower.

Servicing Your Cub Cadet Riding Mower

Step 1: Gather Your Materials

• Tools (socket or spanner wrenches, filter wrench, deck scraper, wire brush)
• Engine oil filter
• Engine oil: 10W-30
• Spark plugs: Plugs for the most common engines used are Kohler RC12YC or Kawasaki BPR4ES. Check your engine & spark plug to confirm the correct replacement plug.
• Inner & outer air filter
• Fuel filter
• Grease
• Spray lubricant
• Rubber gloves, work gloves, and safety glasses
• Plastic funnel
• Oil drain pan
• Rags or paper towel
• Mower blades if not reusing current blades
• Fuel stabilizer if storing your Cub Cadet for the off-season
• Cardboard or newspaper to cover the work surface

Step 2: Prepare Mower for Maintenance

Park your mower on a flat-level surface. Lay cardboard or newspaper on the ground to collect to protect the surface from oil drips. Allow your Cub Cadet to run for a few minutes to warm up your engine oil. Warm oil flows better than cold oil for draining. Shut off the mower.

Before working on your Cub Cadet riding mower, you must take the following safety precautions to prevent the mower from starting and moving while you are working on it:

• Set your parking brake.
• Remove your ignition key. I like to place it in my pocket or hide it if there are other people in the area
  just to be safe.
• Disconnect the spark plug wires.
• Take caution when working around your engine as it may still be hot.

Step 3: Change Your Cub Cadet Engine Oil & Filter

Place your oil drain pan under the drain plug or drain hose, whichever type your Cub Cadet uses. Use a rag to clean the areas around the oil fill and oil drain areas to prevent debris from entering the crankcase before you proceed with changing your oil.

• Remove your drain plug and allow the oil to run into the drain pan. Your drain plug will be located under the hood on the side of your engine. You will find it near the bottom of your engine.
• Remove your oil dipstick so the oil flows faster.
• Reinstall the drain plug once the oil has completely drained.
• Replace your oil filter with a new filter. Use a filter wrench to assist with loosening your oil filter. Place a light film of fresh oil on the seal before replacing it.
• Add new oil to your crankcase until it is at the proper level. Use your dipstick to check for the correct oil level. It’s important to bring your oil level to the proper level and not overfill.

  Overfilling your crankcase can hurt your engine. If you do overfill the crankcase, you must remove a little oil.

• Wipe off any spilled oil on your Cub Cadet and properly dispose of your used engine oil. Dispose at a recycling center or check with your local auto parts store to see if they accept used oil for recycling.

Step 4: Check Spark Plug and Gap

Inspect your spark plug and gap. I choose to replace my spark plugs once a year during the routine full service of my mower. If you don’t replace them, clean your plugs if they are dirty.

You may experience intermittent running and starting issues from dirty spark plugs or spark plugs that are incorrectly gapped. Do not reattach your spark plug wires until you are done servicing your mower.

Step 5: Remove Dirt & Debris from Your Cooling Fan and Engine Area

Your engine needs to be kept cool while it is running. A clogged cooling fan can prevent air from circulating around your engine block and cylinder. Remove any debris around your fan and the engine area.

Step 6: Remove Dirt & Debris from Your Hydro Fans and Transmission Area

The hydro fans keep your hydraulic transmission cool. Clean the dirt and debris from the fans and your transmission area

Step 7: Clean Battery Terminals

Make sure your battery terminals are clean and make a good connection. If they are showing signs of corrosion, clean them with a baking soda and water solution consisting of 2 cups of water and 3 heaping tablespoons of baking soda. Use a wire brush to clean your terminals.

Step 8: Remove Debris Around Electrical Components & Wiring

Check your electrical components and wiring for debris. Remove any debris you find. Debris can hold moisture and cause your electrical components to prematurely corrode and fail.

Step 9: Check Your Air Filter & Replace it if Needed

I typically change my inner and outer air filters with new filters during a full service. The air filter is your first line of defense to prevent dirt from entering your engine and causing damage. It’s best to keep these filters clean. Excessively dirty air filters can cause engine damage.

Step 10: Replace Your Fuel Filter

Remove your fuel filter and replace it with a new filter. There should be an arrow on the side of your inline fuel filter indicating the direction of fuel flow. Install your fuel filter correctly using the arrow on the fuel filter.

Step 11: Check Your Cub Cadet Fuel System for Leaks

Check over your fuel system to make sure all hoses are securely connected and there are no signs of fuel leaks.

Leaks can develop when there are punctures or cracks in the fuel lines, components are not sealing correctly or plastics are degrading. For all areas to inspect for fuel leaks on your Cub Cadet riding mower, check out this article.

Step 12: Check Your Tire Pressures

Check your tire pressures using a tire pressure gauge. Uneven tire pressures can cause your mower deck to sit unlevel giving you a bad cut. A low tire can also cause steering issues with your Cub Cadet riding mower.

Confirm your lug nuts are secure after making sure your tire pressures are at the psi level shown on the sidewalls of your tires. The pressures must be equal on the left and right-hand tires of your mower.

Step 13: Remove Your Cub Cadet Mower Deck

It’s easiest to adequately clean the top and bottom of your mower deck by removing the deck. Make sure your parking brake is on, the PTO is off and the deck is in its lowest position.

• Do this if your Cub Cadet has a manual PTO then follow the standard steps for removing the deck: Loosen the hardware on the right and left idler pulleys, but do not remove them.

  Remove the hex screw that holds the rod in place over the engine pulley and remove the rod. Remove the PTO cable and unhook the spring by removing the pin that attaches the cable to the bracket on the deck.

  Proceed with the standard steps for removing a Cub Cadet deck

• Move the deck drive pulley: Place a ratchet wrench into the square hole of the idler bracket and turn until the pulley is moved in the forward position.
• Remove the belt around the PTO pulley
• Remove the deck lift arms: There is a cotter pin located at the end of the deck lift arm near the rear of the mower. You will find a pin on both the left and right-hand sides of the mower. Remove these pins and then slide the deck pin out of the lift arms to remove the lift arms from the deck.
• Remove the front lift rod: You will find the lift rod toward the front of your mower. There will be another cotter pin attaching the rod to the deck.

  Remove the pin and slide the rod out of the bracket. To get the rod out of your way, you can adjust your deck lift lever to the highest position.

• Slide deck out from under mower: Confirm you no longer have any items attaching the mower deck to your Cub Cadet and slide your deck out from under your mower.

Step 14: Remove Dirt and Debris on the Top of Your Mower Deck

Remove dirt and debris from the top of your Cub Cadet mower deck. Debris can get collect causing restriction in the movement of the tensioner bracket or hindering the movement of your belt along the pulleys. If your mower uses belt covers, remove them to clean around your pulleys.

The collection of dry materials on your deck can pose a fire danger. The heat from the friction of a deck belt can build up causing a potential fire hazard when combined with dry debris.

Step 15: Check Pulleys and Belts

Now that your mower deck top is clean, make sure the pulleys and belts are in good condition. First, look at your belt.

If it appears worn with a glazed shiny appearance; or it is cracked, stretched, or shredded, you must replace your Cub Cadet deck belt. Need help installing your belt? Check out this guide on replacing a Cub Cadet belt.

Check your pulleys by slowly rotating them by hand. They should rotate smoothly. Replace your pulleys if you feel any resistance or hear noise coming from the bearing as you rotate the pulley.

If your pulley happens to be rusty, clean the rust off the pulleys or replace them if they are very rusty.

Step 16: Scrape the Deck & Check Your Mower Blades

Gain access to the bottom of your Cub Cadet mower deck.

• Check the bearings in your spindle housings for damage by grabbing a hold of each blade and rocking it up and down.

  When you feel movement or hear a knocking noise, remove your spindle housing and check for damage. Replace any bad bearings or replace the whole cutter housing assembly.

• Remove and sharpen your mower blades, and replace them if necessary. To find out more about when you need to replace or sharpen your blades read this guide on changing and sharpening your mower blades. Install your new or sharpened mower blades.
• Scrape your mower deck to remove grass clippings and dirt using a deck scraper or metal brush. A clogged mower deck will affect your cut quality and cause additional strain on your Cub Cadet’s engine. The moisture in the debris can also prematurely corrode your mower deck.

Step 17: Reinstall the Mower Deck & Check the Deck Level

Now that you are done with your mower deck maintenance, slide your mower deck back under your mower. Reattach your mower deck in the reverse order you took it off.

Adjust Cub Cadet Mower Deck Side-to-Side
With your mower deck on a flat level surface, adjust your deck lift to the middle position. Measure from the ground to the blade tip on the right side of the mower. Do the same on the left side of the mower. If the two measurements are not the same, make the following adjustment:

• Adjust the left adjustment rod under the rear fenders. Loosen the upper nut, but do not remove it. Adjust the lower nut clockwise to raise the left side of the deck and counter-clockwise to lower the deck.
• Once your mower deck level on each side of your deck is even, tighten the top nut.

Adjust Cub Cadet Mower Deck Pitch Front-to-Rear

To adjust your mower deck pitch, first, start off by confirming your mower is on a flat level surface. Adjust your deck lift to the middle position.

• The front of your mower deck needs to be 1/4” to 3/8” lower than the rear of the deck. Make the adjustment as necessary by adjusting the stabilizer bracket. You will find an out and inner nut on the front of the stabilizer bracket. Loosen the outer nut, but do not remove it.
• Raise the front of your mower deck by tightening the inner nut and lower it by loosening the lock nut. Once the front of your deck measures between 1/4” and 3/8” less in the front than it does in the rear of the deck, retighten the outer nut.

Step 18: Check Safety System

Your Cub Cadet is equipped with a safety system. Follow the guide in your owner’s manual to make sure your safety system is working as it should. Skipping this step can compromise your safety. You never know when you are going to need it.

Step 19: Replace Damaged, Worn or Missing Parts. Secure Hardware.

Check over your mower and replace all damaged, worn, or missing parts so your mower is in good operating condition. All hardware needs to be in securely in place.

Step 20: Grease Lubrication Points on Your Cub Cadet

Grease your front wheels, front axle, and deck wheels. You will find a grease zerk on each of these items. Properly lubricate your lift linkages, pivot points, and brake to ensure they are able to move freely.

I use a tube of high-performance grease and a spray lubricant.

Step 21: Wash the Cub Cadet & Allow it to Dry Completely

Wash your Cub Cadet with a garden hose to clean any remaining dirt from the mower. If you choose to use a pressure washer, do not use high pressure as this can damage sealed bearings.

Once you are finished washing it, you need to let it completely dry.

I like cleaning my mower on a sunny day. Having a breeze is a plus. Leaving it in the sun to dry allows the moisture around your electrical components and other areas of your mower to evaporate and completely dry.

Using a leaf blower to blow air on your mower can also assist with drying the mower. Any moisture left in the mower can cause premature corrosion of your mower’s components. Read more about cleaning your mower here.

If you need to move your mower to a different area for washing and drying, don’t forget to reattach your spark plug wires so your mower starts.

Step 22: Do This if Your Cub Cadet is Going into Storage for the Off-Season

• Remove fuel from your gas tank OR add a fuel stabilizer to reduce gumming in your fuel system. Check out why I recommend using Sea Foam Motor Treatment.
• Fully charge your battery so it does not freeze during storage OR remove and store in a cool dry location.

How Often Should You Change Engine Oil on a Cub Cadet Riding Mower?

Change your engine oil after every 50 hours of use and prior to placing your Cub Cadet riding mower in storage. You must perform your initial oil change on a new engine after the first 5 hours of use.

Having Problems with Your Cub Cadet Riding Mower?

I put together a list of common Cub Cadet problems and solutions to help you better identify the items you need to address to troubleshoot your mower. You can find this guide at, “Common Cub Cadet Mower Problems”.