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MA-4-5 Accelerator Pump Part help

chuckwn

Well Known Member
Finally figured out why my engine would not start in cold temperatures. The accelerator pump had failed. Specifically, the plunger arm wore out and fell out.

I can't figure out what the part number is for this part. I found A119-557 here:

https://www.expaircraft.com/PDF/marvel-schebler-OH.pdf

but this part number seems to be obsolete.

Any help appreciated.
 

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Update

Does not look like you can buy just the arm. I bought the whole assembly.

P/N PLUNGER ASSY, PUMP - 194-605--F
 
Your entire carburetor looks like a great candidate for O/H or replacement. That is a very old & not updated carburetor. Russ
 
I agree with Russ. If the plunger shaft is that worn then the carb case is equally worn. And I would have to believe that the butterfly shaft and bushings are shot as well. Thus letting air to be sucked in. Same problem with the mixture shaft.
And if you don’t have or can’t make the special tools, it’s best to send it off, or just get a rebuilt unit and send this one in as a core.
I’m just guessing here but I bet it’s hard to set the mixture in flight. With it going lean then rich. And back and forth throughout the flight depending on how bumpy it is.

Hope this helps
RD
 
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