SEB09-3A & SEB09-5A

[CBogle]

Dear Fellow Members:

Once again, I have received two service letters from Cessna that I can't tell if they apply to my aircraft or not. My aircraft is a 1948 170 with a C145-2 and the original carb that was overhauled by G&N with new float kit 666-915 in 1998. The first services bulletin is SEB09-3A, "Carburetor Throttle Body to Bowl Screw Inspection has been issued to transmit Teledyne Continental Motors Service Bulletin SB08-7 and Precision Mandatory Service Bulletin MSA-14."

The second is Owner Advisory Service Bulletin SEB09-5A: "Carburetor Float Replacement - Continental Engine Airplanes has been issued to transmit Teledyne Continental Service Bulletin SB08-6 Precision Airmotive, LLC MAndatory Carburetor Service Bulletin MSA-13 and PRecision Service Bulletin MSA-13 Replacement of Carburetor Floats with New Foam Floats."

I'm sure I"m not the only member to have received these letters from Cessna and probably not the only one that is wondering, do either or both of these apply?

Thanks,

Curt - N4288V

[CBogle]

Additional Information:

MY carb is an MA3SPA Model 10-3237, SN 3965518 with the following history:

63-22-03 New Style Float Installed 666-915
69-24-03 N/A due to model number and ser number
72-06-05R2 C/W insp one time
92-15-16 N/A due to MFG Date Stamped on Float
88-02-04 N/A due to model
89-04-02 N/A due to model

Thanks,

Curt - N4288V

[db99577]

I opened the Cessna letters tonight. My perceptive wife asked "how much"?
Russell Smoot of Plane Maintenance just installed a rebuilt Precision Airmotive carburetor on our 170 during annual two weeks ago. I'll quiz Russell as to what affect/effect this'll have on us.
On a positive note, the rebuilt and adjusted carb makes a huge difference. Runs much smoother now. Especially idle at low RPMs. I always felt the need to idle at a little higher RPM than necessary due to rough noise. 850+ as opposed to the current idle of 650-700 RPM.
On a referral note, Russell & crew have made recent upgrades and annual an satisfying experience. Excellent work at more than fair rates.
Dwayne

[GAHorn]

These recently issued Cessna Bulletins SEB09-3A and SEB09-5A are causing consternation due their recency...yet they address issues which have been known for over a year.
Basically, they refer to TCM Service Bulletins regarding Marvel-Schebler carburetors mfr'd by Precision...which company no longer exists, but has been absorbed by another company.

The two bulletins involve two known problem with older carburetors...the first, SEB09-5A involves floats, namely brass or hollow-plastic (polymer) floats. Either may be perforated for various reasons and can "sink" and cause flooding. Flooding can lead to an engine fire or a poorly-running engine. If it occurs in-flight it may go undetected until fuel exhaustion occurs.

The second bulletin, SEB09-3A, involves improperly or poorly-assembled carbs which were overhauled by Precision in the period immediately before their sale to another company. The assembly might have been improperly torqued and therefore the carb bowls may leak fuel, indicated by fuel-stains at the seperation-gasket.

Both Cessna bulletins refer to TCM bulletins which describe the actual inspections and repairs. Members may access/download those bulletins free at the MX Library section of this forum.

[db99577]

Tnx
Sounds like Russell did not install a defective carb, so I'll have to connive another method of getting a soda outa him.

[canav8]

Sorry to post this on both threads but it is important.

Hi all, I would like to add to this timely topic. During my Annual, I discovered non compliance with the floats,the venturi and the throttle shaft service bulletins, so I ordered an overhauled Kelly Aerospace MA-3SPA. I got it with an overhaul date of Mar. 28th. So when I installed this carb 6/25/09 I just got the Cessna Service bulletins dated 4/27/09. I realized that the carb may not be in compliance due only to paperwork.

I placed a few calls to Kelly Aerospace. It turns out that this is a firefight between Precision Aeromotive and Kelly Aerospace that has generated these bulletins. It all has to do with who is going to be liable if the finger starts pointing. Interesting note. The float bulletin does not apply to Kelly Aerospace carbs. Kelly Aerospace data plate. They have a Brass float in there with a different design then Precision had. The Service letter about the float bowl screws does apply to all Marvel Shebler carbs as the have the same identical design with no revisions. The float bowl screws can vibrate loose in some instances so the letter is valid. It is an easy compliance procedure for most of us, but I would like to ask you consider using torque seal on the screws to see if they have moved. This will be the easiest way to see if the screws need to be serviced.

*Word of caution for all autogas STC guys*
Knowing your not allowed to use ethanol in fuel, It is important to check, but if you use these foam floats as recommended, caveat emptor, the alcohol could eat the floats. Brass floats by Kelly Aerospace would be the most reasonable way of compliance to this service letter, if you are concerned. V/R Doug

[170C]

Seems we replaced the floats in our carb's some yr ago due to a problem with the older ones. Can't remember if we replaced brass ones with plastic ones or the other way around. My carb was overhauled when I did my major in '99 & hasn't been opened up since. I guess if it ain't broke I won't fix it.

[lowNslow]

Any idea who is carrying the recommended "foam filled" floats?

[Roesbery]

Seems to me that some years back there was a similar deal on the floats. Everybody was suposed to change to the new foam type floats and not long after they had to be replaced because the foam acted like a sponge and sank. Sounds like somebody is recycling the same song and dance as before.

[David Sbur]

http://www.cessna120-140.org/forum/viewtopic.php?t=7073

A similar thread on the 120-140 website. Of interest is the post of letters from the FAA regarding compliance.

[GAHorn]

http://www.cessna120-140.org/forum/viewtopic.php?t=7073

A similar thread on the 120-140 website. Of interest is the post of letters from the FAA regarding compliance.

To summarize: A "mandatory" service bulletin is NOT mandatory...unless you are a commercial operator.