Lawn Mower Troubleshooting Guide
Before calling a service centre, work through this guide. 80% of common mower problems can be fixed in under 30 minutes with basic tools.
Problem: Won't Start at All
- Check for fuel — obvious, but often the cause
- Check fuel freshness — petrol older than 60 days is suspect. Drain and refill with fresh
- Check spark plug wire — reconnect if it fell off
- Check spark plug — remove, inspect for fouling, try a replacement
- Check oil level — many mowers have a low-oil cutoff that prevents starting when oil is low
- Check the safety bail — the handlebar dead-man switch must be fully engaged
Problem: Starts But Cuts Out After 30 Seconds
Classic symptom of a dirty carburettor needle valve. The engine picks up the small amount of fuel in the carb bowl, then stalls when the float valve can't supply more. Solution: spray carburettor cleaner into the air intake while it runs briefly, or remove and clean the carburettor.
Problem: Running Rough / Vibrating
- Unbalanced blade — remove and check balance on a nail. Grind heavy side until balanced
- Bent blade — always replace a bent blade, never bend it back
- Loose blade bolt — retorque to 60–90 Nm (check manual)
- Engine mount bolts loose — check and tighten all four
Problem: Leaving Strips of Uncut Grass
- Dull blade — sharpen or replace
- Deck clogged with compressed grass — clean underside thoroughly
- Too fast mowing pace — slow down, especially in thick grass
- Wheel height not matching deck height — all four wheels should be at the same height setting
Problem: Excessive Smoke
Blue/white smoke: Oil burning. Mower was tipped with wrong side down (oil entered combustion chamber) — let it run upright for 5–10 minutes and it usually clears. Persistent blue smoke suggests worn piston rings — may need professional service.
Black smoke: Rich fuel mixture. Clogged air filter is most common cause — clean or replace immediately.
Problem: Self-Propel Drive Not Working
- Drive belt worn or snapped — inspect under the deck, replace if frayed or broken
- Drive cable stretched — adjust cable tension per manual
- Drive wheels worn — rubber teeth on drive wheels wear down over time
FAQ
Can I use premium unleaded petrol in my mower?
Regular unleaded (95 RON) is fine. Avoid E10 (10% ethanol) blends for storage — ethanol absorbs moisture and degrades faster. If E10 is the only option, use fuel stabiliser and don't store more than 30 days.
