Powered Paragliding Ontario - Wallbro 32 carburetor adjustment on Walkerjet paramotors

This article will help you get the most power end efficiency out of your Walkerjet Simon through carburetor adjustment.

The Wallbro carburetor supplied with all Simon models is Model WB 32. It has 2 mixture adjustment screws - HIGH jet screw and LOW jet adjustment screw. The high jet is for high rpm adjustment, and the low jet is for low rpm adjustment. The high jet can be distinguished by the fact that is a T shaped screw, one that you cannot adjust by a screw driver. See picture below.

To add more fuel into the carburetor during operation (enrich the mixture) one must loosen the screw. To restrict fuel and add more air (lean out the mixture) - one must tighten the screw. Note: The higher the altitude of operation, the leaner the mixture must be. Higher altitudes do not have as much air, and in order to have the power output necessary, the motor must be able to breathe. One can however seize the motor by leaning out the mixture too much. This is caused by too much air and not enough fuel to lubricate all the internal parts, resulting in excessive heat and subsequent seizure.

The following is the standard set-up that comes from the factory for sea-level operation: Low - turned counter clock wise 1/2 rotation from fully closed. High - Turned counter clock wise 3/4 rotation from fully closed. IDLE screw turned all the way in clockwise. NOTE: Be gentle when turning both screws clockwise looking for closed position as excessive torque could damage needle seat at the bottom of each screw. It is advisable to run the motor rich at the above factory setting for the first 1 hour, regardless. This will ensure proper lubrication of all internal engine parts.

After 1 hour of operation, this is the advisable procedure to tune the carburetor:

Start with factory setting of HI and LOW jet screws. Again with LOW - turned counter clock wise 1/2 rotation from fully closed. HIGH - Turned counter clock wise 3/4 rotation from fully closed. IDLE screw turned all the way in clockwise.

Once you have done that, run the unit for 3 minutes at 1/2 rpm. Take the spark plug out and check color. The color of the spark plug should be cinnamon brown. If it is lighter than that, you need to loosen the LOW screw by 1/8 revolutions and try this process again. If it is darker than that, you can afford to tighten the HIGH screw 1/8 of turn and repeat. The spark plug color is a good indicator as to how rich/lean your motor is running. If the spark plug color is gray or white, the mixture is WAY too lean and needs to be richened up. If the spark plug color is black, you can lean the mixture out. The engine is not going to be damaged by a mixture that is too rich, but it will get damaged if the mixture is too lean although running your engine rich produces more vibrations that in turn can crack your muffler bracket or "shake off" other parts.

Well, most of you will say "How the heck am I supposed to turn the LOW screw if the engine is vibrating". It is impossible to do and I am afraid my screw driver will end up in my prop. Well, I do not blame you for your concerns. I have super glued a bent nail with one end flattened by hammer to fit into the grove of the LOW screw so it can be now turned by hand. See picture above.

Once you land take the spark plug out and check color. Again, the color of the spark plug should be cinnamon brown. If it is lighter than that, you need to loosen the LOW screw by 1/4 revolutions and try this process again. If it is darker than that, you can afford to tighten the High screw 1/8 of turn and repeat.

You can also just hold the machine on the ground (with help of someone who is very strong) but this is very dangerous as the XC or RR have tremendous amount of power and can easily overpower you and your helper. The above procedure is much better and safer. Also, make sure that if you do this on the ground it free of any gravel, small rocks and sand as at full power prop will pick up anything and may, but probably will, get damaged.

Symptoms	Reason	Fix
Engine vibrates and idle is slow	Idle screw (3) not adjusted properly	Turn idle screw clockwise till engine runs smooth but does not push while at idle.
The idle RPM is too high and engine pushes while at idle	Idle screw (3) not adjusted properly or throttle cable is too short	Turn idle screw counterclockwise till engine runs smooth but does not push while at idle. If this does not help the cable stop (4) may need to be adjusted - move it further away from the leaver
I start pushing the throttle trigger but the engine RPM will not start increasing until the throttle trigger is pushed in 1/3 or more	Throttle cable is not adjusted properly - it too loose	Move the cable stop (4) closer to the leaver
Engine does not run smooth at 15 - 50 % of power.	The low RPM mixture too rich	Turn LO screw (2) 1/8 clockwise
Engine does not react quickly enough to follow fast throttle changes at 15 - 50 % of power. The engine hesitates to accelerate fast enough.	The low RPM mixture too lean	Turn LO screw (2) 1/8 counterclockwise
Engine does not run smooth at 50 - 100 % of power.	The high RPM mixture too rich	Turn HI screw (1) 1/8 clockwise
Engine does not react quickly enough to follow fast throttle changes at 50 - 100 % of power. The engine hesitates to accelerate fast enough.	The high RPM mixture too lean	Turn HI screw (1) 1/8 counterclockwise
Engine stalls when full power is applied	The high RPM mixture too lean	Turn HI screw (1) 1/4 counterclockwise