After months of storage, your small engine equipment needs a quick check before you fire it up. Skipping this step is how you end up with a mower that won't start, a generator that surges, or a chainsaw that runs for 30 seconds and dies. This checklist works for any small engine — mowers, generators, pressure washers, trimmers, and blowers.
1. Check the Fuel First
This is the number one cause of spring start-up failure. If you didn't use fuel stabilizer last fall, the fuel in the tank is likely stale.
What to do:
- Smell the fuel. If it smells sour, varnish-like, or like old paint, it's bad. Drain it.
- Look at the fuel. If it's dark, cloudy, or has visible particles, drain it.
- If the fuel looks and smells fine, you can try using it — but have fresh fuel ready.
When in doubt, drain it. Stale fuel is the cause of 80% of spring no-start problems I see. Dispose of old fuel at a hazardous waste facility — never pour it down a drain or on the ground.
2. Check the Oil
Pull the dipstick and check the oil level and condition. If the oil is:
- Low — top it off to the full mark
- Dark and gritty — change it before starting
- Milky or frothy — moisture has contaminated the oil. Change it immediately and check for a blown head gasket
- Overfull — fuel may have leaked into the crankcase. Drain and refill to the correct level
Never start an engine with low or contaminated oil. You risk seizing the engine.
3. Inspect the Air Filter
Remove the air filter and check its condition:
- Paper filter: If it's visibly dirty or dark, replace it. You can tap it gently to remove loose dirt, but don't blow it out with compressed air — it damages the filter media.
- Foam filter: Wash it in warm soapy water, rinse, let it dry, and apply a small amount of filter oil.
- Dual-element: Clean or replace both the paper and foam elements.
A clogged air filter causes hard starting, surging, and power loss. It's a $10–15 part that prevents major problems.
4. Check the Spark Plug
Remove the spark plug and inspect it:
- Correct gap: Check your owner's manual for the gap spec (typically 0.030" for most small engines). Use a feeler gauge to verify.
- Fouling: If the plug is black and sooty (rich), oily (worn engine), or covered in tan deposits (normal), clean or replace accordingly.
- Electrode wear: If the electrode is rounded or eroded, replace the plug.
A new spark plug costs $3–6 and is one of the easiest ways to improve starting and running performance.
5. Check for Fuel Leaks
Before starting, inspect the fuel lines, filter, and carburetor for cracks or leaks. Rubber fuel lines dry out during storage and can crack. If you see any fuel seepage, replace the line before starting — a fuel leak near a hot engine is a fire hazard.
6. Prime and Choke Correctly
Most spring start-up failures come from incorrect starting procedure, not a mechanical problem:
- Primer bulb: Press it 3–5 times until you see fuel flow through the line (if visible)
- Choke: Full choke for a cold engine. As soon as it sputters, push the choke halfway in, then fully in once it runs smoothly
- Throttle: Set to fast/run position after starting
Don't over-prime — flooding the engine makes it harder to start. If you smell fuel after priming, the engine is likely flooded. Wait 5 minutes, then try starting with no choke and full throttle.
7. First Start-Up
Pull the starter cord (or turn the key) smoothly and steadily. Don't yank it to the end of the rope — let the engine do the work. If it doesn't start after 5–6 pulls:
- Stop and reassess — don't keep pulling until the battery dies or your arm gives out
- Check for spark, fuel, and air in that order
- Search your specific symptom on Lil Engine for a model-specific guide
Once it starts, let it run for 2–3 minutes at idle to warm up, then run it at full throttle for a few minutes to burn off any storage residue.
After the First Start
- Listen for unusual noises — knocking, rattling, or squealing
- Watch for smoke — blue smoke (oil burning), black smoke (rich), white smoke (condensation — normal for a minute)
- Check for leaks under the engine
- Let it run for 10–15 minutes before putting it under load
The Bottom Line
A 5-minute spring check prevents the most common start-up failures: stale fuel, dirty oil, clogged filters, and fouled spark plugs. Do this every spring and your equipment will start reliably and run cleanly all season.