The ROTAX 861189 is a certified OEM replacement pair of carburetor floats used in Rotax 912 and 914 engine series equipped with Bing carburetors. These floats are part of the fuel metering system inside the carburetor float chamber and are responsible for maintaining correct fuel level for stable mixture formation.

This part number was introduced as a replacement for earlier float versions (such as 861185 and 861188) due to documented manufacturing deviations that could cause increased float weight and reduced buoyancy. The updated 861189 floats ensure correct fuel regulation and compliance with Rotax service bulletins for affected engines.

Each carburetor uses a matched float pair, and installation must always be performed as a set to ensure balanced buoyancy and correct fuel shutoff behavior. The floats operate via a mechanical needle valve system that opens and closes fuel flow based on fuel level in the float chamber.

Rotax specifies strict weight limits for float sets and requires correct dry weighing during maintenance to ensure safe operation and prevent flooding or lean running conditions.

Key features include:

Certified OEM Rotax carburetor float set (pair)
Designed for Bing carburetors on Rotax 912 / 914 engines
Replaces earlier float versions due to service bulletin updates
Critical component for fuel level regulation in float chamber
Ensures proper air-fuel mixture stability across operating ranges
Must be installed and replaced as a matched pair
Subject to strict weight and buoyancy limits (dry-weight inspection required)
Resistant to fuel exposure and long-term thermal cycling
Used in certified and experimental aircraft engine applications
Required compliance item under Rotax service instructions (SB-912-074 / SB-914-056 series)
Direct OEM-approved replacement part for affected carburetors