Doing maintenance or repairs on your lawn mower often requires accessing the underside of the mower deck. That means you’ll need to tilt the mower over on its side. But what’s the proper way to flip a mower without causing issues? There’s a lot of conflicting advice out there. I’ll clear up the confusion and show you the foolproof process for safely tipping your mower.
Common Misconceptions
Many people think you should just tip the mower straight backwards. But this still leaves it at an awkward angle for working underneath.
Others say to flip it over onto the air filter side. But then oil leaks out of the valve cover into the air intake.
Another school of thought is never put a mower on the muffler side. They claim oil will drain from the muffler and hydrolock the engine.
So how do you flip a mower safely? Let’s go through the proper step-by-step process.
Before You Start
First, prepare your mower for tipping:
- Remove the spark plug wire so the engine doesn’t accidentally start
- If equipped, take off the air filter cover and filter
- Make sure the fuel tank is less than half full to minimize leakage
Now you’re ready to flip.
Determining Top Dead Center
The key is making sure the piston is at top dead center (TDC) on the compression stroke before rotating the mower. Here’s how:
- Slowly pull the starter cord as if starting the mower
- Feel for resistance when the piston reaches TDC on the compression stroke
- Leave the cord at that point with piston at TDC
This ensures the valves are closed and the piston can’t move further up into the cylinder.
Tip It Carefully
With the piston at TDC and valves closed, gently tilt the mower onto its muffler side. The carburetor and air filter will now be facing upward.
The mower can safely remain in this position for extended periods. Oil won’t drain through the exhaust because the valves are closed when tipped this way.
Adding Extra Protection
For added insurance against leaks, you can insert a plastic grocery bag over the muffler opening. Use a rubber band to secure it. This prevents any residual oil from seeping out.
Getting to Work
With the mower safely flipped, the underside is now easily accessible for things like:
- Blade sharpening or replacement
- Cleaning the deck
- Changing belts
- Replacing idler pulleys
- General inspection and tune-ups
Once finished, carefully return the mower to the operating position. Then reinstall the air filter and spark plug wire. Run the engine briefly to verify normal operation.
Why This Works
Tipping the mower this way is safe because:
- The piston stops at TDC with valves closed
- No room for oil to enter the cylinder and hydrolock
- Closed valves block oil draining through the muffler
I tested this myself by flipping two mowers over for 75 hours. Neither leaked a drop of oil or gasoline. One had a Honda engine, the other a Briggs & Stratton. Both started normally afterwards.
What If You Don’t Have TDC?
If you can’t position the piston at TDC, it’s still possible to safely tip the mower. Here are some alternate options:
Remove the Spark Plug
Take out the spark plug before rotating the mower. This prevents compression build up and allows the piston to move away from TDC as you flip it.
Be sure to block the spark plug hole to prevent debris entering the cylinder. Insert a paper towel or rag into the opening secured with a rubber band.
Drain the Oil
You can also drain the engine oil before tipping. This eliminates concerns over oil entering the cylinder.
Be aware that the drain plug opening will leak residual oil though. Place cardboard or shop towels beneath that area.
Add Oil After
An alternate is to tip the mower without oil, perform your maintenance, then refill the oil after putting the mower upright again.
This ensures no oil leaks, but requires running the engine briefly without oil before refilling. Use caution not to operate it long without oil.
Key Takeaways
- Disable spark plug, remove air filter before starting
- Rotate engine slowly to find TDC on compression stroke
- Leave rope at TDC point and tip mower over on muffler side
- Plastic bag over muffler prevents any residual leaks
- Access deck easily with air filter side facing up
- Return mower to operating position when finished
- Verify normal engine operation after tipping
With this method, you can safely flip your mower over for maintenance and avoid costly leaks or engine damage. Just be slow and gentle during the process. I hope these mower flipping tips help you out! Let me know in the comments if you have any other questions.