Bing 54 carburator problems
Joining the carburetor to the intake manifold, on the 532 Rotax engine is a Mikuni rubber intake manifold adapter. Two problem areas have been reported with this rubber intake manifold.
The first area is that directly under the clamp used to tighten the rubber manifold to the carb body. It is difficult to locate, since the pilot must remove the carb, and clamp and closing inspect the area.
What has been found is separation or tearing of the rubber. This generally causes erratic running, hard starting, and possible engine failure caused by the leaning of the mixture.
The other area of separation is located around the bolt holes used to connect the rubber flange to the intake manifold. Although his area is easier to inspect, it still must be looked at very closely to find the separation.
This separation has been reported to be caused by the use of regular unleaded fuel with an ethanol additive which has acted on the rubber, an additional factor is the lack of support for the carb body and breather. In most applications these are all supported by this rubber intake manifold.
To help eliminate this problem it is suggested that some way of supporting the carb/breather be found, and that the pilot use premium unleaded fuel.
Most other Rotax engines use a rubber intake tube to join the carb body to the intake manifold, deterioration of this rubber tube due to exposure to UV, and gas has also been reported, and is an area that pilots should check during regular preflight.
Rotax aircleaner advisory
Another reported problem especially in pusher configurations is the air cleaner falling off and coming in contact with the prop. A simple solution is to install a bracket, or clamp, to prevent the airfilter from coming in contact with the prop if it were to come off.
Air Cleaners: The type of air cleaner used on the Rotax engine greatly effects its performance. In fact the engine will not run properly with some air filters. Many pilots have reported being unable to develop full power after installing the ROTAX AIR BOX silencer kit. This kit when used on the Rotax engine requires the rejetting of the engine.
My personal recommendation is not to use either the silencer kit or after muffler, on any ultralight where performance is marginal, since the use of either reduces performance. Several ultralight manufacturers have shipped their kits out using a sponge air filter. This filter is not recommended for most ultralight applications as it is prone to absorb water, especially during early morning, or after rain.
Most current manufacturers are recommending the use of the K& N filter. This filter when maintained correctly has proven to be one of the best on the market.
Click here for K & N Airfilter Service information