Lawn Mower Carburetor Cleaning
Lawn Mower Starts Then Dies
Don't be intimidated by all the pipes and levers. It is straight forward. Take your time, lots of pictures and you'll be fine.
A typical carburetor will have a fuel line, breather pipe, throttle lever and spring. May have a choke lever, depending on choke system.
It'll look like this, dirty, if you have compressed air, blowing off the grime makes seeing components easier.
Remove the gas line - use a screwdriver to pry it off.
Remove the crankcase breather pipe.
Remove the air filter housing bolts, and housing.
Holding the carburetor in one hand, turn it sideways to release the throttle link, spring and choke lever.
Move to a clean area, remove bowl.
Remove the float and needle, this is done by pulling the pin.
The needle will have a rubber tip seal or the seal will be in the seat of the carburetor.
A worn seal turns pink. When seals wear they can cause too much fuel flow or no flow.
Remove the main jet with a flat screwdriver, these jets are made from brass which is a soft metal and will damage easily. Be sure the screwdriver is a good fit.
The dirt collects in the jet because it has small port holes which gas flows through.
Make sure all these ports are clean. Use a strand of wire to push through the holes.
Use carburetor cleaner to clean all the passage ways and port holes.
Spray through the fuel inlet pipe, throttle plate, choke plate, float and needle.
Drain the gas tank completely and change the fuel filter (if fitted). Some mowers have the filter in side the fuel line at the tank or in the tank.
Refit carburetor in reverse order.
This bit gets overlooked, but it's important. Clean out the fuel can. Check it for grit and if you're not sure the gas is good, replace it and use a gas stabilizer (see video below).
Fill mower with gas and turn on fuel.
Your ready to mow, Nice work!
Gas Flow Test
A sealed tank will prevent fuel from flowing.
To test cap, remove fuel bowl and then remove cap, if fuel flows now then gas cap is faulty.
Check the gas tank, look inside for debris blocking the outlet hole.
If you can't see in, remove the out let pipe and check flow, it should by a constant steady flow.
Dirt in the tank is very common and it will slow or block gas flow. Sometimes it may be necessary to remove the tank to clean.
Check flow on lines.
Check the fuel filter, common types are:
Bottle type are easy to check as most are see through. They can't be cleaned.
In line filters are fitted inside the fuel line at the fuel tank. They can be cleaned and reused.
Tank filters are a mesh screen in the bottom of the fuel tank. They can be cleaned and reused.
To test remove the fuel line at the carburetor, no flow suggests a filter/gas tank block.
Remove the float by sliding the pin out. Check the needle seal.
The needle tip seal turns pink when worn, some carburetors will have the seal in the carburetor needle seat instead.
Use fine wire to clean out the needle seat in the carburetor.
Blow some WD carb cleaner into the needle seat on the carburetor.
Fuel should start to flow, if it doesn't, remove and clean carburetor or replace with a new unit.
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