How to Adjust Carburetor on Briggs and Stratton Riding Lawn Mower

It is important to perform regular carburetor maintenance to prevent future hassle down the road. If debris has accumulated in your carburetor’s main fuel jet, use compressed air to blow out the loosened debris and carburetor cleaner to clean. Using a carburetor cleaner can reduce the amount of maintenance, repairs, and downtime you have to deal with while improving the starting of all 2-cycle and 4-cycle engines.

An engine’s carburetor is responsible for directing gas flow between the tank and the engine. When the carburetor is not adjusted correctly, the engine and mower will perform less than optimally. It is possible to adjust the carburetor to adjust the speed, the high speed, and the choke.

Adjusting the Carburetor on a Briggs and Stratton Lawn Mower, Step by Step

Your Briggs and Stratton lawnmower carburetor may need to be adjusted for various reasons. Whatever the reason is, you must adjust the carburetor to its maximum performance if you wish to fix any of these problems.

There are some important tools that you will need for the job. They are-

• Set of Pliers
• Screwdrivers
• Wrench
• Carburetor cleaner
• RPM gauge or tachometer
• Pair of safety gloves

The steps to adjust the carburetor on a Briggs and Stratton lawn mower are given below:

Step 1. Prepare the Lawnmower

In the first step you should park your lawn mower somewhere safe and open and has enough light. The soil should be even and it is better not to do it in the garage. Start your riding mower engine and let it warm up for 5 to 7 minutes. The slow position of the choke lever will bend your mower into the shape of a turtle. At this idle position, listen to the engine noise. Take note of the speed and sound of the engine again after you run it.

After the engine has cooled down, turn off the ignition. Obtain the tools needed for the repair. To prevent the mower from rolling, set the parking brakes in position and set the gear to neutral.

Step 2. Adjust the idle speed mixture

On top of the riding mower engine, place the air filter and air filter cartridge. Remove the air filter and cartridge after the engine has been cooled down and the nut has been loosened. For clearing out accumulated debris and gunk in the carburetor, Gumout recommends spraying carburetor cleaner onto the carburetor. On the carburetor, you will find a screw for adjusting the idle speed. By turning the screw with a screwdriver counterclockwise until the needle just barely touches the seat, tighten the screw. Next, turn it in a counter clockwise direction 1 1/2 times.

Step 4. Adjust the high-speed mixture

In this step you have to adjust the high speed mixture. In order to do so, you must find the high speed adjustment screw which is on the opposite of the idle speed adjustment screw. Carburetors that are older or made by a particular manufacturer may not have the option of adjusting the components. In that case, remove the air filter cover, filter, and cartridge to access the carburetor.

Starting the engine and letting it run for a few minutes to warm up will prevent the engine from stalling. As you turn the high speed screw clockwise, make sure that it touches the seat with its needle. Now turn the screw counterclockwise 1 1/4 turns. But be careful of the cautions of Briggs & Stratton.

The mower will now start when you set the throttle to fast. You must first turn the high speed screw clockwise until the engine slows, then counterclockwise until the engine slows. Now, you need to determine the location of its center. Test the adjustment by moving the throttle from slow to fast and back again. Finally the cartridge, filter, and cover should all be mounted on the mower. And you are done with this step!

Step 5. Adjust carburetor choke linkages

Locate the choke linkage on the carburetor by removing the air filter cover, filter, and cartridge. Press the fast accelerator pedal.

You will need to loosen the bracket that holds the throttle cable casing in place. Release the cable by loosening the screw on the bracket using a screwdriver without taking it completely out.

Using your fingers, move the cable until the carburetor’s choke plate closes. Secure the cable in place by tightening the bracket against the cable casing. The carburetor choke plate will open and close as the throttle is moved from fast to slow, then back to fast.

Step 6. Check the carburetor connections and engine speed

Having cleared the carburetor flow lines is an important step after mixture adjustment. For this reason, ensure the fuel line, air intake, and exit are clean and free of obstructions. Clean them with petrol and dry them in the sun afterward. They can be closed in the same manner as they were opened. Install the tubes properly. Now, start the engine.

If all the steps have been followed correctly, then you have adjusted the carburetor of your Briggs and Stratton engine correctly.

Final Words 

So that was all about how to adjust the Carburetor on Briggs and Stratton riding lawn mowers. If you still face any problems even after following the steps you can contact an expert.