nippaero

nippaero

Well Known Member
I just got my new MS-4SPA carb for my O-320. I have a couple questions on the fuel fitting. In looking at the drawings it looks like an AN823-6D fitting is used to connect the fuel line to the carb. Does the fitting screw directly into the carb? I see in some pictures it looks like there is another fitting that might go in between the AN823 and carb. Is there a screen there?

2) Should I be using a steel fitting here?

MP-4SPA-Carb.jpg
 
Fitting

There is a Marvel Schebler fitting that goes in the carb first, then the AN6 fitting. I prefer to use a steel or stainless AN fitting but it probably doesn't matter because the carb body is aluminum. The special adapter has a fine screen and can be found in the Aircraft Spruce catalog.
 
mine looks like this, and has a washer between it and the carb:
edit: my carb however is an MA-4SPA part number 10-5217
412238579.jpg
 
Last edited:
CATPart said:
mine looks like this, and has a washer between it and the carb:
edit: my carb however is an MA-4SPA part number 10-5217
412238579.jpg
Click to expand...
That is the one, note the straight male thread which requires the special washer. I think the fitting/screen is the same for all MA4SPA carbs.
 
Why would this part not come with a new carb? It is part of the carb, just like a float, just like a needle. Maybe you should check if it should have been included? Or maybe your "new" carb is really a "new to you" carb?
 
CATPart said:
Why would this part not come with a new carb? It is part of the carb, just like a float, just like a needle. Maybe you should check if it should have been included? Or maybe your "new" carb is really a "new to you" carb?
Click to expand...

Yep, if this is a "new" or even rebuilt or overhauled carb, the part you seek should have been included.
 
Thanks guys. I should have been a little more clear. The carb is not "new". It came off a 172 and is going on my freshly overhauled O320. I'll have to look around and see if I can find the fitting somewhere. But at least know what I need now.
 
Just a heads up for down the road, an ma4spa carb jetted for a 172 probably won't be jetted correctly for an RV. (Way more cooling through those fat hole on the nose of a 172). You may be fine, but if you have temp issues, re jet
 
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