Walbro WJ71 Carburettor Setting
Your engine has already been checked and tested at the factory and the carb is set at base settings.
Make sure you complete the run in of the engine on a rich setting before considering leaning it out for
optimal performance. Please remember your climate and altitude could result in the requirement for
different settings, so as with any two stroke, start with caution and care.
We fit the Walbro WJ71 carb as standard which does not come with a priming bowl. However
priming the engine is simple. Pull the engine over with the choke on a few times in order for the fuel
pump within the carb to pull the fuel up the line into the carb itself. Its ideal to use a clear fuel line so
you can watch this process and see when the fuel reaches the carb.
Then you can expect the engine
to fire up, sometimes with the aid of a small amount of throttle and choke.
Location of carburettor controls
Throttle lever
Idle Speed adjustment screw
Low Speed mixture adjustment screw
High Speed mixture adjustment screw
Base setting:- 1 1/2 turns out
Base setting:- 1 3/8 turns out
The base settings of the mixture screws may need some adjustment to suit your local
atmospheric conditions e.g. temperature, humidity. If so adjustments should be made 1/16
of a turn at a time, with a test run after each adjustment. Do not exceed 1/3 turn in from the
factory setting or it may result in engine damage.
Choke lever
Fuel feed connection
Shown in 'OFF' position
Note: The choke is automatically released when the throttle is opened
Note: This carburettor has only one connection to the fuel tank. This is the fuel
feed tube which must have an in tank filter fitted.
There is no fuel return tube required so this should be removed and the hole
blanked off using a suitable sealing plug as long as your tank has a breather, if.
not then fit a MX style non return breather valve in the second unused line.
