SERVICE BULLETIN NUMBER 84

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IMMEDIATE ACTION SERVICE BULLETINNUMBER 84 May 9, 1946 SUBJECT: Winterization of J3C-65 MODELS AFFECTED: J3C-65 Airplanes It has been brought to our attention that, in extreme cold weather operation, the J3C -65 has been giving some trouble due to cold engine operating temperatures. In order to eliminate this hazard and insure better engine operating temperatures, it is considered satisfactory to follow the procedure set forth below. It is suggested that these procedures be followed in temperatures of 400 F or below. 1. All J3C-65 airplanes, with muffler installation, up to serial number 15396. a. The aluminum breather tube (Part No. 84332) can be lagged with 1/16" to 1/8" felt or some similar material which should extend all the way to the bottom of the tube. This lagging will help eliminate the possibility of condensation freezing in the tube. b. To obtain a higher operating oil temperature, it is permissible to lag the oil sump with waterglass and flake asbestos or some similar material which will keep the cold air off the sump and hold the heat in. A material thickness of 1/16" to 1/8" is satisfactory for this lagging. c. The cowl air inlet opening, the first opening under the propeller hub, · should be closed. Piper Part 73951 is a cover plate for this opening. d. In order to insure the highest possible carburetor heat rise, the flat plate valve in the carburetor air box should be checked to see if it is seating properly. This can be done easily by removing the air filter and observing the top edge of the valve, with heat on. The valve should seat flush with the top of the box, with absolutely no air gap. e. The tailpipe shroud assembly (Part No. 70912) can be lagged with asbestos or some similar fireproof material. The recommended thickness of this material is approximately 1/16". PIPER AIRCRAFT CORPORATION, LOCK HAVEN. PA .. U. S. A. Number 84 (continued) Page 2 2. f. The flexible tube which runs from the tailpipe shroud to the carburetor air box can also be lagged with the same material as used on the tailpipe shroud. g. See Figure I. All J3C-65 airplanes, with muffler installation, serial numbers 15396 and up. a. Same as 1. a. b. Same as 1. b. c. Same as 1. c. d. Same as 1. d. e. Same as 1. e. f. Same as 1, f. g. Same as 1. g. h. A stainless steel or aluminum ring can be placed against the bottom of the last tailpipe shroud spacer. This will close off the hot air bleed between the tailpipe and tailpipe shroud. See Figure II. WARNING: The stainless steel or aluminum ring should absolutely never be put in J3C-65 airplanes below serial number 15396, For further information concerning winterization, refer to Piper Service Bulletin No. 47. End. WARNING The carburetor uir preheater must be operuted during icing conditions in FULL ON position. ·e (PARTIAL OPENING PROHIBITED) When such con- 'ditions are encountered and engine misses 0 after applying carburetor heat RETARD throttle · until engine smooths up; advancing the throttle at such times may "kill" the ehgine. ALWAYS use FULL carburetor heat during glides. PIPER AIRCRAFT CORPORATION '------------ FIG- I t1UFFLER TAILPIPE SPACER RING I TAILPIPE SHRCW CLOSE-OFF RING .--hi ,---i L.,____..,_-, ON ASS'Y. SERVICE BULLE. TIN. NO. 64- I DETAIL OF CLOSE-O_Fr RING