Bing 54 carburetors and Bing 54 carburetor parts, Bing carb charts, Bing carb updates.

Adjusting the Bing Carburetor
The Bing Carburetor (36mm) is a three stage system: Idle, Midrange, and Top End System. From the moment the engine is started to approximately 1/4 throttle, the carburetor is running according to how the idle system is set up. As the idler jet number decreases, the mixture gets leaner; (see part# 4), as the number increases, the mixture gets richer. For instance, idler jet #45 has a leaner mixture than idler Jet #50.

The Air Regulating Screw (see part# 28) must be set as stated in the Bing Jet Chart in order to insure smooth operation of the ldler Jet. This screw adjusts the air/fuel mixture at idle speeds and for smooth acceleration. 

Turning this screw in a clockwise direction creates a richer mixture while turning it counterclockwise creates a leaner mixture. 

To adjust this screw, gently turn in a clockwise direction until the screw bottoms out, then loosen the screw (in a counter-clockwise direction) the number of turns as recommended in the Bing Jet Chart. 

For example, the ROTAX 503A would be .5 (1/2 turn) out (effective range 1/2 to 2-1/2 turns out).

 Use the carburetor piston Adjusting Screw (see part# 30) to adjust the idle RPM. Turn this screw in a counter-clockwise direction until the Carburetor Piston (see part# 3) is in the lowest position. Then carefully turn the screw clockwise until it just engages the piston and then continue to turn it clockwise for2 to 2-1/2 full turns. This determines the idle RPM of the engine and should be set at 2,000 RPM.

 The Midrange System affects the carburetor for approximately 1/4 to 3/4 throttle. Once again, the lower the number of the Needle Jet, the leaner the mixture.

NOTE: (Jet needle must always be under plastic spring cup)
The Jet Needle (see part# 2) has grooves which the Holding Plate (see part# 3) can be snapped onto.The grooves are numbered 1. 2, and 3 with number 1 in the top position (note: some jet needles have 4 grooves as in diagram #1 at right).

When the Holding Plate (see part# 3); is snapped onto the top position (#1) of the jet needle, a leaner mixture is created than if it were mounted in the #2 groove.

1. lnstall sieve sleeve by slightly squeezing it by pushing it all the way up the mixing tube.
2. Smaller numbers indicate decreasing jet opening and leaner conditions.
3. The #54 marked on the side of the carb is just a casting mark.
4. Float guide pins should be polished to insure smooth float action.
5. Floats with aluminum guides should be replaced.
6. lnspect jet needle grooves for wear every 50 hours.
7. Float arm should start out parallel to the float chamber base.
8. Fuel pump must be in system on ALL Rotax two stroke aircraft engines - to insure correct fuel flow pressure - this is NOT a gravity feed system! 

The main jets on the Bing carb are replaceable. It is recommended that they be replaced if they are found to be plugged. This can happen when the carb is left with fuel in it for long periods of time. The fuel turns to sludge which plugs the jet. In this situation it is NOT recommended that the jet be cleaned and reused. Main jets start at #120 increasing in increments of 5 to #220 - exceptions are #142/148/152/158/162

The idler jets on the Bing carb are replaceable. It is recommended that they be replaced if they are found to be plugged. this can happen when the carb is left with fuel in it for long periods of time. The fuel turns to sludge which plugs the jet. In this situation it is NOT recommended that the jet be cleaned and reused.
Idler jets start at #30 and increase in increments of 5 to #70

Note on the 582 and 503 DUAL carb Rotax engines we have found that a decrease in the idler jet size provides a smoother engine idle.

We have found that on the 582 Rotax switching to a larger needle jet helps prevent hot spots in the engine between 5200 and 5800 rpm. It also helps prevent engine surging in the same range on the 532 Rotax.

The jet needle and clip should be inspected on a regular basis for wear. Wear occurs in the area where the clip rides. Failure of the clip and or needle will cause the needle to:
A) lower itself causing a LEANER fuel mixture or
B) the needle will fall down into the bottom of the carb causing loss of power.
C) cause erratic engine performance as the needle bounces up and down.

Click on diagram for larger view of parts.

Needle clip part # 963 500 (3)
Bing Carb advisory - needle and clip failure Click here!