So, you forgot to winterize lawn mower last fall. Don’t worry, you’re not alone. It’s a common mistake, but one that can leave you facing a frustrating and potentially expensive problem when spring arrives. This guide will walk you through exactly what to do next. We’ll cover how to assess the damage, the step-by-step recovery process, and how to get your mower running again.
Forgot To Winterize Lawn Mower
First, take a deep breath. All is not necessarily lost. The main risks of skipping winterization are fuel degradation and corrosion inside the engine. Old gas turns into a gummy varnish that clogs the carburetor and fuel lines. Water condensation can also cause internal rust. Your goal now is to adress these issues before you try to start the engine.
Immediate Assessment: Don’t Just Try to Start It!
Resist the urge to pull the cord or turn the key. Trying to start a mower with bad gas or gunked-up parts can cause further damage. Instead, follow these initial inspection steps.
- Check the Fuel Tank: Look inside. Is there old fuel from last season? If it’s more than a couple months old, it’s likely stale.
- Smell the Fuel Cap: Old gas has a sour, varnish-like smell compared to the sharp odor of fresh gasoline.
- Inspect the Oil: Check the dipstick. Does the oil look milky or have a frothy appearance? This indicates water contamination, a serious issue.
- Look for Obvious Damage: Check for rodent nests, chewed wires, or cracked hoses that might of occured over the winter.
The Step-by-Step Recovery Process
Now, let’s get your mower back in working order. You’ll need some basic tools: a socket set, fresh oil, a fuel stabilizer, and a container for old fuel. Always work in a well-ventilated area and disconnect the spark plug wire for safety.
Step 1: Drain All Old Fuel
This is the most critical step. You must remove every drop of the old gasoline from the system. First, siphon or carefully pour the old gas from the fuel tank into an approved container. Do not pour it on the ground or down a drain. Take it to a hazardous waste disposal site.
After the tank is empty, you need to drain the carburetor. Many mowers have a small bolt or drain screw on the bottom of the carburetor bowl. Place a small container underneath and loosen the screw to let the residual fuel drain out. If your mower doesn’t have a drain, you may need to disconnect the fuel line and let it run out that way.
Step 2: Replace the Fuel Filter
If your mower has an in-line fuel filter (a small cylinder in the fuel line), replace it. The old filter is likely clogged with gunk from the degraded fuel. It’s a cheap part and easy to swap. Simply pinch the clamps, remove the old filter, and install the new one in the correct direction (there’s usually an arrow showing fuel flow).
Step 3: Clean or Replace the Spark Plug
Remove the spark plug using a spark plug socket. Examine it. If the electrode is heavily corroded or covered in black deposits, it’s best to just install a new one. They are inexpensive. If it looks fairly clean, you can gently clean it with a wire brush and check the gap with a feeler gauge. A fresh spark plug gives your engine the best chance at starting.
Step 4: Change the Engine Oil
Even if the oil looks okay, change it. Contaminants from the old fuel can find there way into the oil. Run the engine for a minute or two first to warm the oil (if you completed the fuel system flush and it can start). Then, drain the old oil completely and refill with the type and weight recommended in your owner’s manual. This is good practice every season anyway.
Step 5: Clean the Carburetor (The Likely Culprit)
If your mower still won’t start after the steps above, the carburetor jets are probably clogged. You can try using a carburetor cleaner spray. Remove the air filter and spray directly into the carburetor throat while trying to start the engine. This sometimes clears minor blockages.
For a more through cleaning, you’ll need to remove the carburetor. Take pictures as you disconnect linkages and hoses. Disassemble it carefully, soak the metal parts in a carburetor cleaner solution, and use a small wire to clear the tiny jets. Reassemble and reinstall. If this seems daunting, a replacement carburetor for many models is affordable and easier than a rebuild.
Step 6: Fresh Fuel and a Test Start
Once everything is clean and reassembled, add fresh, high-octane gasoline to the tank. For extra protection, you can add a fuel stabilizer to this fresh gas; it won’t hurt and will help for next season. Reconnect the spark plug wire. Prime the engine if it has a primer bulb, and give the cord a pull or turn the key. With luck, it should sputter to life.
Preventing Future Problems: The Correct Winterization Routine
Now that you’ve fixed the problem, let’s ensure you never have to do it again. Here is the simple fall routine to follow.
- Add Fuel Stabilizer: For your last mow of the season, add fuel stabilizer to a full tank of fresh gas. Run the engine for 5-10 minutes to circulate the treated fuel throughout the system.
- Change the Oil: Change the oil while the engine is warm from that last run. Dirty oil contains acids that can corrode engine parts over the winter.
- Remove the Battery (if electric start): Disconnect and remove the battery. Store it indoors on a wooden board and trickle-charge it once during the winter.
- Clean the Mower Deck: Scrape off all grass clippings and mud from underneath the deck. This prevents corrosion.
- Store Properly: Store your mower in a dry, covered place like a shed or garage. Cover it with a breathable tarp to keep dust off.
When to Call a Professional
If you’ve gone through all these steps and the engine still won’t turn over, or if it turns over but doesn’t start, you may have a deeper issue. Significant internal rust from water in the cylinder, a damaged flywheel key, or a compromised engine seal require a pro. If you’re not comfortable with mechanical work, starting with a professional service is always a smart choice. It can save you time and prevent accidental damage.
FAQ: Forgot to Winterize Lawn Mower
Q: What happens if you don’t winterize a lawn mower?
A: The main risk is fuel degradation, which clogs the carburetor and fuel system. Water condensation can also cause internal rust in the engine cylinder and bearings, leading to costly repairs.
Q: Can old gas ruin a lawn mower engine?
A: Yes. Old gas evaporates and leaves behind a thick, sticky residue. This residue clogs the tiny passages in the carburetor, preventing the engine from getting the fuel it needs to run. In severe cases, it can require a full carburetor replacement.
Q: How do you start a lawn mower that wasn’t winterized?
A: Do not try to start it on the old gas. First, completely drain the old fuel from the tank and carburetor. Add fresh gas. If it still doesn’t start, the carburetor likely needs cleaning. Follow the step-by-step guide above.
Q: Is it worth fixing a lawn mower that wasn’t winterized?
A> In most cases, yes. The repair is often a simple carburetor clean or replacement, which is far cheaper than buying a new mower. However, if the engine has severe internal rust or damage, a professional assesment is needed to decide if repair is economical.
Q: What is the one thing you should always do to winterize a mower?
A: The single most important step is to either run the engine until the fuel tank is completely empty, or fill the tank with fresh gas mixed with fuel stabilizer. This prevents the carburetor from being gummed up by old fuel residues.
Forgetting to winterize your lawn mower is a setback, but it’s rarely a death sentence for the machine. By methodically flushing the fuel system, changing the oil, and adressing the carburetor, you can usually restore it to perfect working order. The key is patience and not forcing the engine to run on bad fuel. Once it’s running smoothly, mark your calendar for next fall. A small amount of preventative maintenance saves you a huge amount of time and trouble come spring. Your future self will thank you for it.