Why Your Small Engine Won't Start
In This Guide
A pull cord that goes nowhere is one of the most common calls we get. The good news is that when a small engine won't start, the reason is almost always simple and cheap. This guide narrows it down quickly, whatever the machine, and routes you to the exact fix for a mower, generator, or snow blower.
Start With the Fuel
Fuel is the first suspect, because gasoline goes stale in as little as thirty days. Old fuel gums up the carburetor and will not ignite properly.
- Drain any fuel older than a month and refill with fresh gas.
- Check that the fuel valve is open and the tank is not empty.
- Make sure the choke is on for a cold start.
Check the Spark Plug
No spark means no start. Pull the plug and inspect it. A plug soaked in fuel, coated in black soot, or worn at the tip will not fire reliably.
Clean or replace it, set the gap to specification, and test for a strong blue spark against the engine block while cranking.
Look at the Air Filter
An engine needs air as much as fuel. A filter packed with dust and clippings chokes the engine and can stop it starting entirely. Tap it out or replace it if it is dark and clogged.
The Overlooked Causes
- A blocked vent in the fuel cap, which creates a vacuum and starves the engine.
- A safety switch not engaged, such as a brake bail, seat switch, or kill switch.
- A flooded engine from too much choke, which needs a few minutes to clear.
Match It to Your Machine
The basics are the same, but each machine has quirks. For step by step help see the lawn mower troubleshooting guides, or the generator and snow blower start guides for those units.
Rather Let a Pro Come to You?
Wildwood Small Engine Repair brings the shop to your door. Over 10,000 repairs since 2019, house calls from $75 and tune-ups from $38, backed by a 4.9 star rating. Call 888-594-5516 to book same week service.