RAF has recently received two or three reports from EZ pilots who have experienced problems with floats that become fuel logged and sank in the float bowl. This of course will result in a very over-rich condition and could kill the engine unless the mixture is immediately pulled out to almost idle cut off. RAF has tried to find out what could be causing this problem and we hear rumors that a major AF (Airworthy Directive) is in the pipeline and should be published soon concerning this problem.
Apparently the composite floats installed in virtually every Marvel Schebler carburetor is susceptible to this problem and may have to be replaced with a metal float. Keep a sharp eye out for an unexplained over-rich condition. The engine will generally start to run rough, and may even quit. If this occurs, try leaning the mixture control. If this helps, get back on the ground and pull the carburetor. Have it inspected by a competent carburetor rebuild company.
If you have recently noticed you are leaning your mixture more than you used to, suspect that this may be the problem. Do not continue to fly. This can be a very serious problem. The company that owns Marvel Schebler carburetors Is: Facet Aerospace Products Co. #1410 Highway, 70 Bypass, Jackson, TN 38301 (901)423-2500 This company has issued a service bulletin #A1-84A. This bulletin says the float must be replaced at the next 100 hour inspection or if any of the following three symptoms are seen.
1. Evidence of a flooding
2. Rough running at low throttle settings.
3. Inconsistent engine shut down.
If your engine is doing any of the above, contact your local carburetor dealer. Here in southern California, our dealer is:
475-479 Riverside Dr.
Tell them the model of Marvel Schebler carburetor and they have a repair kit which includes two or three gaskets, a clip and pin and a new metal float. For the MA3 carburetor, the repair kit part number is #666915.