AD 69-24-03

69-24-03 MARVEL-SCHEBLER: Amdt. 39-881. Applies to Marvel Schebler Models MA-3-A, MA-3-PA, MA-3-SPA, MA-4-SPA, MA-4-5, MA-5, MA-4-5-AA, MA-6AA, and HA-6 carburetors of the following listed part numbers and serial numbers installed on the Continental, Franklin and Lycoming model engines as specified below, to wit:

ENGINE MANUFACTURER & MODEL CARBURETOR MODEL CARBURETOR PART NUMBER CARBURETOR SERIAL NUMBERS CONTINENTAL

A-65 & A-75 Series MA-3-PA A-10-4233 P-22-460 thru P-22-464 O-200 Series MA-3-SPA A10-4115-1 AV-4-4094 O-200 Series MA-3-SPA A10-4894 BE-14-10218 thru BE-15-11672 C-85 Series MA-3-SPA A10-4240 AU-15-235 thru AU-15-244 C-90 Series MA-3-SPA A10-4252 Q-23-2422 thru Q-23-2436 C-145 Series MA-3-SPA A10-4895 BF-14-3598 thru BF-15-3655 O-470-K MA-4-5 A10-3965-12 H-3-6894 thru H-3-6896 O-470-R MA-4-5 A10-4893 BD-13-3946 thru BD-15-4660 FRANKLIN

4A-235 Series MA-3-SPA A10-4654 BN-3-112 thru BN-3-130 GA-335 Series MA-5 A10-4865 BC-14-530 thru BC-16-706 6V-350 Series MA-5 A10-4809 BA-14-203 thru BA-14-207 6A-350 Series MA-5 A10-4865 BC-14-530 thru BC-16-706 LYCOMING

O-235 Series MA-3-A A10-3103-1 Y-30-3132 thru Y-30-3275 O-235 Series MA-3-A A10-4953 BV-0-268 thru BV-0-538 O-235 Series MA-3-PA A10-4978-1 BQ-3-252 thru BQ-3-276 O-235 Series MA-3-PA A10-5050 BY-0-100 thru BY-1-291 O-290 Series MA-3-SPA A10-3346-1 B-35-342 thru B-36-359 O-320 Series MA-4-SPA A10-3678-32 A-25-14781 thru A-26-16246 O-320 Series MA-4-SPA A10-5009 BL-5-2632 thru BL-5-3435 O-360 Series MA-4-5 A10-3878 G-34-4651 thru G-36-5362 O-360 Series MA-4-5 A10-4164-1 K-27-6460 thru K-27-6602 O-360 Series MA-4-5 A10-5034 BU-0-283 thru BU-0-383 O-360 Series HA-6 A10-5045 BW-0-198 thru BW-4-550 VO-435 Series MA-4-5-AA A10-4025-12 Z-16-2304 thru Z-18-2434 TVO-435 Series MA-6-AA A10-4438-1 AH-19-3676 thru AH-21-4067 O-540 Series MA-4-5 A10-4404 R-24-6530 thru R-26-6916 O-540 Series MA-4-5 A10-4404-1 AO-20-3571 thru AO-23-3829 O-540 Series MA-4-5 A10-5042 BS-1-427 thru BS-1-588 O-540 Series MA-4-5 A10-5054 BZ-0-100 thru BZ-0-209 VO-540 Series MA-6-AA A10-4218-1 AK-17-1274 thru AK-19-1478 VO-540 Series MA-6-AA A10-4975 BK-2-125 thru BK-3-148

NOTE: The affected carburetors listed above were manufactured between December 5, 1968, and June 23, 1969. Approximately 25% of these carburetors have been inspected and cleaned by Marvel Schebler or the manufacturers of the engines or aircraft on which the carburetors are installed. Marvel Schebler Service Bulletin A1-69 lists the carburetors remaining to be inspected and covers the same subject matter as this AD. Any carburetor serial numbers included in this AD but not listed on Marvel Schebler Service Bulletin A1-69 comply with this AD, and require no further inspection or cleaning. A logbook entry of compliance and nameplate marking must be made on these unlisted carburetors. The "A" prefix to the part numbers listed above does not appear on the carburetor nameplate.

Compliance: Required within the next 25 hours' time in service after the effective date of this AD, unless previously accomplished.

To prevent possible power losses due to blockage of carburetor metering passeges by thread lubricant or other foreign material, accomplish the following or an equivalent procedure approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region, or Chief, Engineering and Manufacturing Branch, FAA, Eastern Region:

Remove the carburetor bowl drain plug with the aircraft fuel valve in the "ON" position and allow the carburetor to flush for 20 to 30 seconds. The auxiliary pump, if installed, should be operating. After flushing, inspect the drain plug cavity and drain plug for thread lubricant or other foreign material and remove any such material noted. After cleaning, reflush 20 to 30 seconds, reinstall plug approximately one thread into cavity, apply Parker Seal Lube or equivalent on exposed threads and tighten.

NOTE: If practical, aircraft should be positioned so that bottom of bowl slopes toward drain opening during flushing and cleaning. Recommended torque for 1/8" pipe plug is 50-60 in. lbs., for 1/4" pipe plug is 120-144 in. lbs.

After completion of the above, impression stamp or engrave "A1" on a nameplate or apply approximately 1/4-inch diameter dot of yellow enamel or similar permanent material to nameplate.

This amendment becomes effective November 29, 1969.