SB-18, Revision A Issued: 03/15/2011

Original Issue Date: 10/14/2010

Page 1 of 4 Distributed by:

Manufactured By:

1. Applicability: Except as noted in the “Exempted MFB Carburetors” section below, this 

service bulletin applies to all machined from billet (MFB) HA-6

TM carburetors, including 

but not necessarily limited to the following part numbers (including all dash numbers):

10-5219-XX, 10-5224-XX, 10-5230-XX, 10-5235-XX, 10-5253-XX, 10-5255-XX, 10-

5283-XX, 10-6001-XX, 10-6019-XX, and 10-6030-XX, regardless of whether the

carburetor is new, rebuilt, overhauled or used, and regardless of what agency performed 

service on the carburetor(s) in the past. MFB HA-6

TM carburetors are found on various 

Lycoming engine models, possibly on engines made by other manufacturers, and on 

certificated and non-certificated aircraft of various types. This bulletin applies only to 

MFB HA-6

TM carburetors, it does NOT apply to die-cast HA-6TM carburetors. (See Figure 

3 below)

Exempted MFB Carburetors – This bulletin does not apply to MFB HA-6

TM carburetors 

manufactured by Marvel-Schebler Aircraft Carburetors LLC (MSA), formerly known as 

Volare Carburetors LLC and having a serial number listed below. This SB likewise does 

not apply to any MFB HA-6

TM carburetors that MSA serviced after October 10, 2010, or 

to any MFB HA-6

TM carburetor bearing:

A. “IC” number of 17 or higher on the data plate;

B. One of the following or higher serial numbers stamped on the carburetor data

 plate in cases where the original data plate and original carburetor body

 combination remains unchanged;

Marvel-Schebler Aircraft 

Carburetors LLC

125 Piedmont Avenue

Gibsonville, N.C. 27249, USA

Phone: 336-446-0002 // 0005

Fax: 336-446-0007

Email: customerservice@msacarbs.com

Website: www.msacarbs.com

EMERGENCY

Service Bulletin: SB-18 Rev A

Original Date: October 14

th, 2010

Revision Date: March 15th, 2011

SUBJECT: LOOSE MIXTURE SLEEVES

- BEFORE FURTHER FLIGHTAVOID SERIOUS RISK OF INJURY OR DEATH

MN353303 MS385901 VC213901 VC307001 VN041603 VN067103 VN148901

MN353304 MS392501 VC224401 VC334201 VN041604 VN091501 VN158301

MN353305 MS392901 VC230501 VC346701 VN041605 VN091502 VN226403

MN382201 MS392902 VC238401 VC356501 VN041606 VN091503 VN244301

MS357901 MS392903 VC242401 VN026601 VN041607 VN091504 VN244305

 
 

SB-18, Revision A Issued: 03/15/2011

Original Issue Date: 10/14/2010

Distributed by:

Manufactured By:

C. The letters NWP and/or 8-08 (or numbers representing a month and year later than 

August 2008) stamped in the airbox flange and/or the engine flange gasket surface.

(See Figure 1), or;

D. A laser marking affixed to the carburetor by Marvel-Schebler® on the bottom of the 

carburetor float bowl as shown in Figure 2 indicating that the carburetor is in 

compliance with this service bulletin.

MS364001 VC140601 VC242402 VN026602 VN041609 VN091505 VN292901

MS366301 VC140602 VC249201 VN026603 VN041610 VN091506 VN297501

MS366501 VC140701 VC249202 VN026604 VN043801 VN091507 VN298301

MS370501 VC171301 VC249203 VN026605 VN043802 VN091508 VN313804

MS370503 VC171401 VC249204 VN026606 VN043803 VN111203 VN313805

MS372301 VC181101 VC249205 VN026607 VN043804 VN111204 VN314601

MS378301 VC181102 VC260801 VN026608 VN043805 VN111205 VN314602

MS385201 VC181103 VC260802 VN041001 VN043806 VN134001 VN326701

MS385202 VC210701 VC264101 VN041201 VN067101 VN134003 VN326703

MS385203 VC213401 VC264102 VN041601 VN067102 VN134004 VN326704

VN326705

Page 2 of 4

Figure 1

NOTE: If the carburetor body has been replaced, the serial number is not exempt.
 

SB-18, Revision A Issued: 03/15/2011

Original Issue Date: 10/14/2010

Distributed by:

Manufactured By:

CAUTION: Some over-haulers have substituted data plates bearing their own names and/or 

logos on carburetors originally manufactured by MSA or its predecessors. Such obfuscation of 

the actual manufacturer of an aircraft component can lead to confusion as to what service 

bulletins and or Airworthiness Directives apply to what units (see MSA Service Bulletin SB-16). 

Regardless of what name or logo appears on the data plate, this service bulletin applies to every

MFB HA-6

TM carburetor originally manufactured by MSA or its predecessors unless it is 

specifically exempted above.

NOTE: Machined From Billet (MFB) HA-6

TM carburetors can be identified by their faceted, 

milled surfaces (most MFB HA-6

TM carburetors were originally anodized a golden color. Color 

alone should not be the sole factor in determining if a HA-6

TM carburetor was made from billet or 

was die cast. A die-cast carburetor may have been painted or the gold anodizing could have been 

removed from the MFB) See Figure 3 & 4 below. Do not confuse MFB HA-6

TM carburetors with 

die-cast HA-6

TM carburetors.

`

ORIGINAL GOLD

COLOR

ORIGINAL GREY

COLOR

DIE CAST BODY

(Smooth Body)

MACHINED FROM

BILLET BODY

(Faceted Body)

I.C. NUMBER

SERIAL 

NUMBER

Figure 4

Page 3 of 4

Figure 3

Figure 2
 

SB-18, Revision A Issued: 03/15/2011

Original Issue Date: 10/14/2010

Distributed by:

Manufactured By:

2. Reason: Marvel-Schebler® has discovered a very dangerous problem involving loose 

mixture control sleeves or sleeves that might become loose and is issuing this SB to 

inform over-haulers, owners, and operators of serious issues with certain MFB HA-6

TM

carburetors. 

3. Background: This service bulletin is prompted by a reported in-flight loss of engine 

power resulting in the forced landing of an aircraft equipped with a made from billet 

HA-6

TM carburetor. Upon inspection, Marvel-ScheblerTM determined that the carburetor’s 

mixture control sleeve was loose and had rotated in the carburetor body. If a mixture 

sleeve rotates sufficiently it will interrupt fuel flow to the engine.

4. Procedure:

 A. For every affected MFB HA-6

TM carburetor installed on an aircraft, prior to further flight:

i. Remove the carburetor and send it to Marvel-Schebler® for inspection and 

possible repair before re-installing on the aircraft;

ii. Replace the carburetor with a serviceable MFB HA-6

TM carburetor of the 

proper part number that is exempt from this SB; or,

iii. Replace the carburetor with a serviceable die-cast HA-6

TM carburetor of the 

proper part number.

B. For every affected MFB HA-6

TM carburetor in inventory or otherwise not installed on 

 an aircraft, prior to releasing such carburetors for flight, submit such carburetors to 

Marvel-Schebler® for inspection and possible repair.

 

5. Voiding of Warranty and Waiver of Liability: Operation of a carburetor in which other 

than genuine Marvel-Schebler® approved parts are installed voids any otherwise 

applicable warranty and constitutes a complete and total waiver to the extent 

permitted by law of any and all rights the owner, operator and/or service facility or 

repairer may have had to hold Marvel-Schebler Aircraft Carburetors LLC responsible or 

liable for the malfunction or failure of such an aviation carburetor.

6. Safety First: Marvel-Schebler® is a customer-service oriented company committed to 

technical innovation in pursuit of aviation safety. While Marvel-Schebler®has no 

authority to compel owners to act responsibly and take prudent action to insure their own 

safety and the safety of others, Marvel-Schebler®believes compliance with this 

EMERGENCY Service Bulletin is important and will help to insure safer, better

maintained and better performing products.

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