Lawn Mower Starts Then Dies
Lawn Mower Starts Then Dies
- Stale/Dirty Gas
- Faulty Choke
- Gas Filter Blocked
- Gas Tank Blocked
- Gas Line Blocked
Mower Won't Stay Running
Tools You'll Need
This carburettor is too bad to clean.
Replacing is easy and the right repair for a badly gummed carburettor.
This carburettor is repairable, gumming is a carburetor killer.
Using a stabiliser at the end of the season will save you time, stress and money.
What's A Carburettor?
Choke set to full to start a cold engine. The flap should be closed.
As the engine warms a little, move the choke to the fast/run position. The choke should be off at this point.
Check that it's moving to the off position.
Your mower may not have a choke, it may instead have a priming bulb.
It has the same end result as the choke plate - gives the engine extra gas for cold engine starts.
The jet feeds a measured amount of gas to the engine.
If the port holes block, they restrict gas flow which causes a mower to stall, lack power or just not start.
Dirt in the bowl is common and cleaning it will often have you back mowing.
When replacing the bowl, don't over tighten and be careful not to pinch the bowl seal.
Float & Needle
Needle and float together control gas flow to the fuel bowl.
Any supply problems here will cause poor engine performance.
Fuel Bowl Feed Bolt
Not every fuel bowl will have the fuel feed bolt. It's a hollowed out bolt that has a fuel feed port hole, it feeds gas to the jet.
If your mower has one, it must be very clean.
Cleaning The Gas Bowl
When working on your mower, remove the plug wire.
This prevents accidential starts.
Turn off the fuel tap (if fitted), if not use a grips to gently squeeze fuel line.
If your gas is old, drain the tank. Remove an easy to access gas line or drain out through gas bowl.
The fuel bowl lives behind the air filter. It will be fixed to the carburettor by one bolt, usually.
Honda fit a handy drain bolt, which allows you drain the bowl without removing. Nice!
Some Briggs and Stratton carburettor bowls are held on by a hollow bolt, its other function is to feed fuel to the main jet.
These hollow fuel feed bolts are prone to clogging.
Not all mowers have this fuel feed bolt. If you have, be sure to clean it. I pluck a wire strand from a wire brush to clean the bolt fuel feed hole.
If you have some carb cleaner, spray some up the main fuel jet.
Turn the fuel tap on. Now with the fuel bowl removed check fuel flow. A good flow should be seen when the float is in the dropped position.
No flow when the float is in the up position.
Clean and refit the bowl, take care to seat it correctly.
The seal not seen in this picture will usually stay on the the carburettor, sometimes it will come off with the bowl.
If your fuel is fresh turn it on, fit the plug wire and give it her a try.
If your mower still runs poorly - Clean carburettor.
What's A Mower Engine Tune-up?
- Remove air filter
- Remove fuel line
- Empty & clean gas tank
- Remove carburettor
- Remove carburettor bowl, float & needle
- Remove and clean the jet
- Reassemble and mow