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Greg; We have additional problems with the AD 2002-16-04. I suspected that
the tubes would not fit on the O-200 with the Marvel carburetor. They also
will not fit on a C-75 or C-85 with the Marvel carburetor. The Marvel
carburetor No. A10-4240 was available as original equipment by Continental
Motors as PN 627637. There is also an STC which modifies the O-200 Marvel
carburetor to allow it to be used with the C-75/85.
I tried putting the support tubes that come with kit No. SK-76 on a
1946 415-D serial 2113. This Coupe has the Marvel carburetor which was
installed at the Continental factory in 1965, after the engine had been
remanufactured. As you stated, the tubes will not fit.
The problem appears to arise from the fact the tubes were designed
for the Stromberg carburetor. The Stromberg was more readily available,
less expensive and most often used. The Stromberg has the fitting for the
fuel inlet on the rear of the carburetor, and the Marvel has the fuel
inlet fitting on the side of the carburetor. This changes the geometry
completely, and requires both an elbow and nipple on the Stromberg, but
only a nipple on the Marvel carburetor.
There was a different set of tubes made for the Forney, which had
the C-90 with the larger oil tank. These tubes both attach to the valve
pushrod housing studs instead of the forward one on the stud and the rear
one on the lower engine mount.
Although the AD note was written to address the problems of
gascolator support, unfortunately it spells out specific part numbers that
must be used. The part numbers that are supplied can be modified to fit,
the engines with Marvel carburetors, but both tubes must be shortened in
order to fit properly. This requires bending the tube end to shorten the
tube and drilling a new hole. The change will be different for the O-200
powered Coupes, because of the larger oil tank, than it will be for the
C-75/85 Coupes with Marvel carburetors.
It appears that once again the FAA and Univair have written an AD
note without properly researching the universe which it will affect. I
will attempt to contact both Univair and the Manager of the Denver ACO,
who are responsible for the AD.
The AD is written so that an alternative means of compliance can be
authorized, however it requires inspection by your local principal
maintenance inspector and his/her comments to be added to your request for
alternative compliance. Good Luck on getting this accomplished within the
next 25 hours time in service allowed after September 13th.
Lynn Nelsen
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