How to Adjust a Briggs & Stratton Pulsa Jet Carburetor

Updated February 21, 2017

The Briggs and Stratton Pulsa Jet carburettor regulates fuel flow on the aluminium series of engines. The most common application of this carburettor is for small horsepower lawnmowers and rototillers. The Pulsa Jet carburettor resides above the on-board gasoline tank. Fuel is drawn up into the device through two fuel suction lines. A single needle valve resides near the rear of the carburettor unit, that faces the push handles of the mower or rototiller. The needle valve has a slot-type screw head.

Close the needle valve with the screwdriver in a clockwise direction.

Open the needle valve 1 1/2 turns in a counter-clockwise direction. This setting allows the engine to be started and warmed to operation temperature. Keep the air filter in place for correct adjustment.

Start the engine according to the manufacturer's instructions for the device. Accelerate the engine to operational speed.

Turn the needle valve in a clockwise direction, closing it, until the engine begins to lose speed. Slowly back the needle valve out, counter-clockwise direction, until the engine smooths out.

Test the engine under a full-load condition. Mow grass with the lawnmower or cultivate soil with the rototiller. Turn the needle valve slightly in a counter-clockwise direction if the engine loses speed while under full-load conditions. It may take several minor adjustments to the needle valve in order to get the best performance from the engine.


Use only fresh gasoline in the engine when performing the above adjustment as old gasoline will cause the engine to operate erratically. If the device fails to adjust properly after following the above steps, the two fuel suction lines may be clogged. There are small screens in the ends of both plastic tubes. The carburettor must be removed from the fuel tank and the lines or screens cleaned.

Things You'll Need

  • Slot head screwdriver
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