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MA-4-5 carb, how do I know if I have the brass float?

kevinh

kevinh

Well Known Member
Hi ya'll,

I have a Marvel-Schebler MA-4-5 carb on my ECI O-360-A1A. It was purchased new with my engine and manufactured approximately 9/2004. A couple of recent threads made me realize I had somehow missed service bulletin MSA-13 and I'm trying to decide when/how I want to handle this.

After reading: http://www.vansairforce.com/community/showthread.php?t=32931

I gather the original metal floats were only an issue once they had a lot of time. But then Precision decided to switch to a plastic float that was apparently awful. Service bulletin MSA-13 says that any (non overhauled) carb with a revision less than "IC-15" needs the new foam float. My carb is revision "IC-6".

My question: From that revision (or date of manufacture) do any of ya'll know if my carb has the plastic float or the original brass model? In other words, when did precision switch from brass to the crummy plastic float?

I'm asking because if it is the brass I think I'll wait a bit longer to replace it than if it is the apparently crummy plastic float.
 
Last edited:
Where'd they go?

I saw that engine out thread and tried to look up the old Marvel AD's last night. It's been awhile and they're kinda Jurassic so it hasn't been an issue lately, but I couldn't find them. In 64 an AD said to remove all metal floats & replace with black ones. Plate was then stamped 64. Then another AD superceded and said to replace all black floats with metal and stamp MF on data plate. I thought metal floats were still current and standard, but I couldn't find the AD under MS, Facet, or Precision. Where'd it go?
 
aerhed said:
I saw that engine out thread and tried to look up the old Marvel AD's last night. It's been awhile and they're kinda Jurassic so it hasn't been an issue lately, but I couldn't find them. In 64 an AD said to remove all metal floats & replace with black ones. Plate was then stamped 64. Then another AD superceded and said to replace all black floats with metal and stamp MF on data plate. I thought metal floats were still current and standard, but I couldn't find the AD under MS, Facet, or Precision. Where'd it go?
Click to expand...

I'll check for MF - if mine is metal float I'll wait a while before switching to foam. The thread I linked to has a link to a Lycoming SB that includes the MSA-13 SB (issued 7/2008).
 
AERHED

I have seen this same problem, twice. I talked with the folk at Kelley Aerospace, and was told that if the letters MF were stamped into the data plate there there was an approved Kelley Aerospace Brass (metal) float installed. In my case there was no MF stamp, so I obtained a Kelley Aerospace Float kit, and opened my MA4-5 carburetor. There was a yellowish foam float in there. The carb was purchased new in 1983. I replaced it easily using the excellent instructions included in the kit, and it has been flawless since then. Like you, the mystery to me is where is the Service bulletin that says the foam float should be replaced with a KAPS (Kelly Aerospace Power systems) brass float? I have never found this doc, and only have the word of the man I spoke to at KAPS. There is a doc that says if you have a KAPS brass float installed you do not need to comply with Service bulletin MSA 13

Mikey12
 
My new in 2003 Lycoming O-360 was marked IC 6 and when I took it apart it had the same white float. It now has the Kelly metal float. The change was easy, just follow their well written instructions.
 
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