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©2010 by Avco Corporation All Rights Reserved.  Lycoming Engines is a division of Avco Corporation, Avco Corporation is a wholly owned subsidiary of Textron, Inc. 

MANDATORY 

652 Oliver Street 

Williamsport, PA  17701 U.S.A.

Tel.  570­323­6181

Fax. 570­327­7101 www.lycoming.com

DATE:  June 4, 2010  Service Bulletin No. 342F

(Supersedes Service Bulletin No. 342E)

Engineering Aspects are

FAA Approved 

SUBJECT:  Fuel Line (Stainless Steel Tube Assy.) and Support Clamp Inspection and Installation 

MODELS AFFECTED:  All fuel injected Lycoming engines indicated in fuel line and clamping diagrams.

TIME OF COMPLIANCE:  Check every 100 hours, annual inspection, overhaul and any time fuel lines or clamps 

are serviced, removed or replaced. There have been instances of fuel line breakages where support clamps have been omitted during field overhaul or

repair. The support  clamps  dampen line vibration due to the impact  of cooling air and vibration from the engine

and/or aircraft. Also, the fuel supply lines between the fuel injector manifold and the nozzles can become damaged 

and leak if they are severely bent or kinked during engine maintenance. As  a means  of minimizing the  hazards of fuel line damage, the following inspection of fuel lines  and clamps is 

required.

1. The fuel lines to the nozzles are made from 1/8 inch tubing. A separate line supplies fuel to the intake port of

each cylinder. Check each line visually for any evidence of physical damage such as: · Dents · Pits · Nicks · Stains caused by fuel leakage

2. Remove any line that  appears faulty. Do not  attempt to repair any line that  leaks. Bent  lines  may be

straightened; however, any line with an inside radius less than 5/8 inch must be replaced. Do not reuse any 

line that  is  dented;  cracks  can develop  at  the site of a dent. Also inspect solder joints at  ends  of lines for

cracks. Replace cracked lines, they cannot be repaired. See the latest revision of Service Instruction No. 1301 

for superseded fuel line identification, bending requirements and replacement information.

3. Examine the location of the clamps that secure the lines to the engine and compare them with the diagrams 

shown in this bulletin. If clamps are missing, replace the fuel line and install clamps as indicated. Do not use

plastic tie straps. Also, examine the lines to ensure the clamps securely support the line. Also look for signs of

chafing. Replace fuel lines that show indications of chafing and/or have loose clamps.

4. Older engines that used metal clamps with no cushion must use the P/N LW­12598 fuel line sleeve at each of

those clamping locations. The fuel line sleeve is not used with the cushioned clamps. Any cushioned clamp,

where the cushion has deteriorated or is missing, must be replaced with a new cushion clamp.

5. Compliance with the bulletin must be noted in the aircraft log book. NOTE: If difficulty is experienced when installing clips on a cylinder fuel injector line due to aircraft

baffling, the clips may be installed in positions that provide clearance. Do not permit fuel lines 

to  contact engine or airframe baffle hardware; maintain minimum clearance of 3/16  inch

between a fuel line and any engine or airframe surface.

SERVICE BULLETIN
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LEGEND FOR PARTS ON DIAGRAMS 1 TO 33

(Fuel Lines, Clamps, Brackets, Attaching Hardware as shown in the following Engine Diagrams)

CALL

OUT

PART NUMBER  PART NAME

1  76356  TUBE ASSY., Manifold to nozzle fuel line

2  76357  TUBE ASSY., Manifold to nozzle fuel line

3  76358  TUBE ASSY., Manifold to nozzle fuel line

4  76359  TUBE ASSY., Manifold to nozzle fuel line

5  76360  TUBE ASSY., Manifold to nozzle fuel line

6  76361  TUBE ASSY., Manifold to nozzle fuel line

7  76362  TUBE ASSY., Manifold to nozzle fuel line

8  LW­12098­0­100  TUBE ASSY., Manifold to nozzle fuel line

9  LW­12098­0­140  TUBE ASSY., Manifold to nozzle fuel line

10  LW­12098­0­150  TUBE ASSY., Manifold to nozzle fuel line

11  LW­12098­0­160  TUBE ASSY., Manifold to nozzle fuel line

12  LW­12098­0­170  TUBE ASSY., Manifold to nozzle fuel line

13  LW­12098­0­180  TUBE ASSY., Manifold to nozzle fuel line

14  LW­12098­0­190  TUBE ASSY., Manifold to nozzle fuel line

15  LW­12098­0­200  TUBE ASSY., Manifold to nozzle fuel line

16  LW­12098­0­210  TUBE ASSY., Manifold to nozzle fuel line

17  LW­12098­0­220  TUBE ASSY., Manifold to nozzle fuel line

18  LW­12098­0­230  TUBE ASSY., Manifold to nozzle fuel line

19  LW­12098­0­240  TUBE ASSY., Manifold to nozzle fuel line

20  LW­12098­0­260  TUBE ASSY., Manifold to nozzle fuel line

21  LW­12098­0­270  TUBE ASSY., Manifold to nozzle fuel line

22  LW­12098­0­280  TUBE ASSY., Manifold to nozzle fuel line

23  LW­12098­0­300  TUBE ASSY., Manifold to nozzle fuel line

24  LW­12098­0­310  TUBE ASSY., Manifold to nozzle fuel line

25  LW­12098­0­320  TUBE ASSY., Manifold to nozzle fuel line

26  LW­12098­0­340  TUBE ASSY., Manifold to nozzle fuel line

27  LW­12098­0­350  TUBE ASSY., Manifold to nozzle fuel line

28  LW­12098­0­390  TUBE ASSY., Manifold to nozzle fuel line

29  LW­12098­0­412  TUBE ASSY., Manifold to nozzle fuel line

30  LW­13995­0­202  TUBE ASSY., Manifold to nozzle fuel line

31  LW­13995­0­224  TUBE ASSY., Manifold to nozzle fuel line

32  LW­13995­0­271  TUBE ASSY., Manifold to nozzle fuel line

33  LW­13995­0­284  TUBE ASSY., Manifold to nozzle fuel line

34  AN735­26  CLAMP

35  LW­16226­10­03*  CLAMP

36  LW­16226­10­25  CLAMP

37  LW­16226­10­38*  CLAMP

38  LW­16226­10­44*  CLAMP

39  LW­16226­10­75*  CLAMP

40  LW­16226­25­13*  CLAMP

41  LW­16226­25­25*  CLAMP

42  LW­16226­25­38*  CLAMP
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LEGEND FOR PARTS ON DIAGRAMS 1 TO 33 (CONT.)

(Fuel Lines, Clamps, Brackets, Attaching Hardware as shown in the following Engine Diagrams)

CALL OUT PART NUMBER  PART NAME

43  LW­16226­25­44*  CLAMP

44  LW­16266­25­50*  CLAMP

45  LW­16266­25­63*  CLAMP

46  LW­16266­25­75*  CLAMP

47  71824  CLAMP

48  73843**  CLAMP

49  74733  CLIP

50  STD­692  SCREW, No. 10­32 x 1/2 long 

51  STD­860  SCREW, No. 10­32 x 5/8 long 

52  STD­921  SCREW, No. 10­32 x 7/8 long 

53  STD­1925  SCREW, 1/4­20 x 5/8 long 

54  STD­425  WASHER, No. 10 plain 

55  STD­28  WASHER, No. 10 plain 

56  STD­670  NUT, No. 10­32 self­locking 

57  72815  BRACKET, 90°, Twist

58  73136  BRACKET, 90° 

59  73152  BRACKET, Support clamp 

60  75837  BRACKET, Fuel line support

61  76735  BRACKET, 90° 

62  LW­14875  BRACKET, 90° 

63  75414  BRACKET, Fuel manifold 

64  76868  BRACKET, Support clamp 

65  74278  BRACKET ASSY., Fuel line support

66  73626  BRACKET, Extension 

67  73318  BRACKET, Extension 

68  LW­25­0.81  BOLT, 1/4­20 x 13/16 long 

69  STD­8  WASHER, 1/4 plain 

70  STD­160  WASHER, 1/4 lock 

71  STD­1411  NUT, 1/4­20 plain 

72  AN735­32  CLAMP

73  AN735­36  CLAMP

74  STD­969  SCREW, No. 10­32 x 1/2 long 

75  STD­251  WASHER, No. 10 lock 

76  73966  SPACER 

77  STD­1916  SCREW, 1/4­20 x 1­1/8 long 

78  LW­25­1.13  BOLT, 1/4­20 x 1­1/8 long 

79  STD­1874  SCREW, 1/4­20 x 13/16 long 

80  AN4­13A BOLT, 1/4­28 x 1­13/32 long 

81  LW­12598  SLEEVE

82  LW­25­0.50  BOLT, 1/4­20 x 1/2 long 

*  See page 4 for part number designation. **  P/N 73843 is superseded by P/N LW­16266­25­13 

NOTE

Aircraft quality Phillips head screws of proper length may be used in place of specified Lycoming screws.
IS

SUEDREVISEDPAGENO. REVISION

MODAYYEAR MODAYYEAR 

03  24  72  06  04  10  4 

of 42 F

S.B. 342
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Diagram No. 1  ­­ IO­320­B1A 

IO­360­B1B, B1F, B2F, B2F6, B4A, F1A, L2A, M1A 

AEIO­360­B1G6, B1H, B4A, H1A, H1B

LIO­360­M1A 

NOTE: Underlined engine models indicate new engine model added to the list
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Diagram No. 2  ­­ IO­320­B1A, B1C, C1A, D1A, D1B, E1A, E1B, E2A, E2B

LIO­320­B1A, C1A 

AEIO­320­D1B, D2B, E1B, E2B

IO­360­B1G6, C1C, C1C6, C1D6, C1E6, C1F, C1G6 

LIO­360­C1E6 

HIO­360­C1A, C1B, E1AD, E1BD, F1AD 

TIO­360­A1B
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Diagram No. 3  ­­ IO­360­A1A, A1B, A1B6, A1B6D, A1C, A1D, A1D6, A2A, A2B, A3B6, A3B6D,

B1D, B1F, B2F, C1A, C1B, C1D6, J1A6D, M1B

HIO­360­C1A, C1B

AEIO­360­A1A, A1B, A1B6, A1D, A1E, A1E6, B1F, B2F
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Diagram No. 4  ­­ IO­360­B1E
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Diagram No. 5  ­­ HIO­360­A1A
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Diagram No. 6  ­­ HIO­360­A1B
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Diagram No. 7  ­­ HIO­360­B1A (View 1 of 3) Rosette Installation
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Diagram No. 8  ­­ HIO­360­B1A (View 2 of 3) LW­12155 Manifold Assy., Fuel
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Diagram No. 9  ­­ HIO­360­B1A (View 3 of 3) 75282 Manifold Assy., Fuel
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Diagram No. 10  ­­ HIO­360­D1A
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Diagram No. 10A  ­­ HIO­360­G1A
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Diagram No. 11  ­­ AIO­320­A1B, B1B, C1B

AIO­360­A1A, A1B, B1B
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Diagram No. 12  ­­ TIO­360­C1A6D  (View 1 of 3)
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Diagram No. 13  ­­ TIO­360­C1A6D  (View 2 of 3)
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Diagram No. 14  ­­ TIO­360­C1A6D  (View 3 of 3)
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Diagram No. 15  ­­ IVO­360­A1A
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Diagram No. 16  ­­ IGO­480­A1B6
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Diagram No. 17  ­­ IO­540­C4D5D, G1C5, K1A5, K1A5D, K1B5, K1F5, K1F5D, K1G5, K1G5D,

K1H5, K1J5, K1J5D, K1K5, AA1B5 

NOTE: Underlined engine models indicate new engine model added to the list
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Diagram No. 18  ­­ IO­540­A1A5, G1A5, G1B5, G1D5,  G1E5, G1F5, K1A5, K1B5, K1C5, K1D5,

K1E5, K1E5D, K1F5, K1H5, K1J5, P1A5, S1A5, T4A5D, T4B5, T4B5D, T4C5D,

AA1A5 

TIO­540­U2A, AE2A, AH1A 

LTIO­540­U2A
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Diagram No. 18A  ­­ IO­540­AE1A5
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Diagram No. 19  ­­ AEIO­540­D4D5 

TIO­540­AF1A, AF1B, AG1A, AA1AD, AB1BD
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Diagram No. 19A  ­­ IO­540­AB1A5 ̈

TIO­540­AK1A 

 ̈ Note manifold orientation.
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Diagram No. 20  ­­ IO­540­AC1A5 

TIO­540­AJ1A
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Diagram No. 21  ­­ IO­540­A1A5, C1B5, C1C5, C4B5, C4D5D, D4A5, J4A5, L1C5, AB1A5 ̈

TIO­540­C1A, E1A, G1A, AB1AD 

AEIO­540­D4A5, D4B5, L1B5, L1B5D, L1D5 

 ̈ Note manifold orientation.
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Diagram No. 21A  ­­ IO­540­N1A5, R1A5, V4A5, V4A5D, W1A5, W1A5D, W3A5D
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Diagram No. 22  ­­ IO­540­B1A5, B1C5, E1A5, E1B5
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Diagram No. 23  ­­ TIO­540­A1A, A1B, A2A, A2B, A2C, F2BD, J2B, J2BD, N2BD, R2AD 

LTIO­540­F2BD, J2B, J2BD, N2BD, R2AD
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Diagram No. 24  ­­ IO­540­M1A5, M1B5D
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Diagram No. 24A  ­­ IO­540­M1C5
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Diagram No. 25  ­­ TIO­540­S1AD
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Diagram No. 26  ­­ TIO­540­V2AD, W2A 

LTIO­540­V2AD, W2A
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Diagram No. 27  ­­ IGO­540­B1A, B1C
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Diagram No. 28  ­­ IVO­540­A1A
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Diagram No. 29  ­­ TIVO­540­A2A
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Diagram No. 30  ­­IO­720­A1A (View 1 of 2)
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Diagram No. 31 ­­ IO­720­A1A (View 2 of 2), A1B, D1B, D1BD, D1C, D1CD
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Diagram No. 32  ­­ IO­720­B1B, B1BD
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Diagram No. 33  ­­ IO­720­C1B