Dealing With Grass Buildup Under A Lawn Mower Deck

There are all sorts of thing you will have to do to assure that your lawn mower performs well. One is to regularly clean out the grass buildup under the lawn mower deck. The task can be achieved fairly easily, but it will take some time out of your Saturday or Sunday.

Cleaning out the underside of the mower’s deck is an essential part of the maintenance program. Overtime clumps of grass stick to the deck and this could cause rust and result in messy, slow cutting because of reduced airflow. Cleaning the deck and then spraying its surface with a protective coating will slow down grass buildup.

Tools and other materials you will need to perform this task include:

• Gardening gloves
• A flat pry bar
• Metal putty knife or wire brush
• Air hose with nozzle or wand
• Dish or decreasing soap and water
• Pressure washer
• Non-stick cooking spray or vegetable oil
• Graphite, silicone or Teflon spray
• Rust protection product

Cleaning The Grass From The Underside Of The Mower’s Deck

1. Empty the gas tank.
2. Tilt the mower so that you have access to the underside of the deck.
3. Prop the mower up securely so it can’t fall and cause injury.
4. Remove the spark plug or disengage the spark plug wire to assure that the mower will not start by accident and detach the blade.
5. Use the flat pry bar and your hands to scrape off the clumps of grass from the underside of the deck.
6. Scrape off the remaining remnants of grass from the lawn mower deck with the metal putty knife or wire brush. Wet the underside of the deck with water if the grass is difficult to scrape off.
7. Use the air hose to blow off any remaining grass.
8. Remove the mower’s air filter and determine if it needs to be replaced. If it is in good condition and washable, use the air hose to blow off grass and other debris. Be careful not to tear the filter.
9. Use the soap and water to wash off the filter.
10. Shake off excess water and blow dry the filter using the air hose and then let dry before re-installing.
11. If hand scraping hasn’t removed the grass, spray the underside of the lawn mower deck with a pressure washer.
12. Leave the mower propped up and lit it dry completely before continuing. You can also use the air hose to speed up the drying.
13. Spray the underside of the lawn mower deck with non-stick cooking spray or spread vegetable oil with a clean rag on the surface. This serves as a cheap and short-term way to reduce grass build up and make it easier to scrape away the grass the next time you clean under the deck.
14. Graphite, silicone or Teflon sprays are also available at hardware stores. Cover the entire surface of the underside of the clean, dry deck with the spray and then let dry. The effect is the same as cooking oil, but will last longer.
15. If you have tried a lubricant to prevent rust and were not happy with the results, consider using a rust protection product. Check the ingredients of the product to assure that it isn’t based on the same solution as the lubricant. Read the instructions concerning surface preparation and safe application.
• A lanolin-based rust prevention spray such as Fluid Film leaves a non-drying coat on the surface. This could cause grass to stick to the coating. It is suggested that you test it first on a small portion of the deck.
• Rust spray that includes cold galvanization compound is water resistant for unpainted metal surfaces. This may be ideal if you live in a wet climate. However, dirt and debris will wear it down.

Re-install the air filter, spark plug or spark plug wire and the blade.

Changing Your Mowing Scheme

lawn mower
Not cleaning the underside of your mower deck not only effects the manicuring of your grass, but if left caked on over periods of time, will have disastrous results with the mower’s performance. Image courtesy of Bahrns Equipment, an authorized Toro Dealer.

Ways to minimize grass from sticking to the underside of the deck is to do your mowing when the grass is dry. Keep in mind that grass may have more internal moisture than you think for as long as a day or two after it rains.

It is also advised that you mow regularly. The longer the grass, the more likely they will clump.

It is also suggested that you run the mower at full throttle. If you run it at slower speeds, then the clippings and reduced airflow makes it more difficult to eject the clippings.

If the lawn you mow is small, then check the underside of the mower’s deck once or twice a week to ascertain if it needs cleaning. If you use your mower several days a week, then check under the deck once every one or two weeks.

If grass buildup continues to be a problem, then consider exchanging the mower’s blade with a high lift blade. This style of blade increases airflow and ejects clipping with more force.

Also keep in mind that if you use mulching blades they may be more likely to cause grass buildup on the underside of the deck.

About Robert Janis

Written by Robert Janis for LawnEq - Your specialists for Lawn Mower Parts and Small Engine Parts. We offer genuine premium OEM parts for Land Pride, Toro and many more dependable manufacturers.