Complete 2-Stroke Engine Winterization Guide

1 Stabilize or Drain Fuel System

Most critical step - prevents 90% of winterization problems

Option A: Fuel Stabilizer (Recommended)

1. Add fuel stabilizer to tank (follow package instructions - typically 1 oz per gallon)
2. Fill tank completely to minimize air space and condensation
3. Run engine for 10-15 minutes to circulate stabilized fuel through entire system
4. Shut off and allow to cool

Best for: Equipment with plastic fuel tanks, modern sealed systems, or if you have quality ethanol-free fuel with good stabilizer.

Option B: Complete Fuel Drain

1. Run engine until fuel tank is nearly empty
2. Remove remaining fuel with siphon or drain screw
3. Run engine until it dies from fuel starvation
4. Pull starter 5-10 more times to clear carburetor

Best for: Long-term storage (6+ months), older equipment, or if you had ethanol fuel.

2 Clean Air Filter & Cooling System

Air Filter:

• Foam filters: Wash in warm soapy water, rinse, squeeze dry (don't twist), let air dry completely, re-oil lightly
• Paper filters: Tap out debris or replace if heavily soiled
• Never store with dirty filter - traps moisture and promotes mold

Cooling System:

• Remove debris from cooling fins with brush or compressed air
• Clean all grass/sawdust from engine exterior
• Check for mouse nests in air intake areas
• Outboards: Flush cooling system with fresh water (see separate section below)

3 Fog the Engine

Protects cylinder walls and piston rings from corrosion

What You Need:

• Fogging oil (available at any auto parts store, $5-10)
• Can be 2-stroke oil in a pinch, but dedicated fogging oil is better

Procedure:

1. Start engine and let it warm up for 2-3 minutes
2. Remove air filter
3. With engine running at idle, spray fogging oil into carburetor throat in 3-second bursts
4. Engine will smoke heavily (white smoke) - this is normal
5. Continue spraying until engine starts to bog down
6. Give one final heavy spray and let engine die
7. Remove spark plug
8. Spray fogging oil directly into spark plug hole (3-4 second burst)
9. Pull starter cord 5-6 times slowly to distribute oil on cylinder walls
10. Reinstall spark plug (or install old plug for storage)

4 Inspect & Service Spark Plug

Two approaches:

Option A: Replace with sacrificial plug

• Install old/used spark plug for winter storage
• Prevents corrosion of good plug threads
• Replace with fresh plug in spring

Option B: Clean and protect current plug

• Remove, inspect, and clean current plug
• Apply anti-seize to threads
• Reinstall snugly
• Note: Check plug condition - if heavily fouled, plan to replace in spring

5 External Cleaning & Lubrication

Clean:

• Wipe down entire exterior with damp cloth
• Remove sap, grease, and oil buildup
• Clean bar and chain (chainsaws) - remove chain and soak in solvent
• Check for loose bolts and tighten

Lubricate Moving Parts:

• Chainsaws: Oil bar rails, adjust tensioner, store chain loose
• Trimmers: Grease gearbox, clean string head, remove trimmer line
• Outboards: Grease prop shaft, steering pivots, and tilt mechanism
• All equipment: Spray WD-40 or similar on metal parts prone to rust

6 Prepare for Storage

• Coil fuel lines and secure with twist ties (prevents kinking)
• Cover exhaust outlet with plastic bag and tape (prevents moisture and pests)
• Cover air intake with tape or plastic (prevents pests)
• Attach a tag noting winterization date and any issues to address in spring
• Store in upright position (prevents oil/fuel leakage)
• Place on wood or cardboard (not directly on concrete - draws moisture)