CARB MA-4SPA 10-5217 question

[RV-7 flyer]

My RV-7 is going through its annual inspection and all has gone well until my A&P looked at my carb, a precision MA-4SPA. He said the secondary fuel tube moves when he touches it. He says it should be brazed and not move at all when touched. Also, I think I need to do the float AD. Any recommendations on who to send it to get repaired or rebuilt. I'm on the west coast. I didn't build the plane, but I know the carb was an overhaul model installed in 2004 (about 500 hours on it). Or should I just send it to Aircraft Spruce for exchange? I'm trying to figure out the cost difference and any advise would be greatly appreciated.
regards,
Joe B.
RV-7

 

[kevinh]

He said the secondary fuel tube moves when he touches it. He says it should be brazed and not move at all when touched.

I'm not sure what you mean about the secondary fuel tube. Are you talking about the small diameter fuel line that goes from the carb up to the fuel pressure sender? I think most folks use SS braided flex line for that line and that is a good thing.

Or are you talking about the primer line that goes from the primer solenoid on the firewall up to the first two cyls?

 

[hngrflyr]

If it was overhauled in 2004, the Float AD and the Venturi AD Should have been complied with. There should be an "F" and a "V" stamped into the carburetor's data plate. The stamped letters show that the ADs have been complied with.

 

[kevinh]

If it was overhauled in 2004, the Float AD and the Venturi AD Should have been complied with. There should be an "F" and a "V" stamped into the carburetor's data plate. The stamped letters show that the ADs have been complied with.

Hmm - Does a single F mean that the metal float has been replaced with the 'old' plastic float? If so, does that mean that he still need MSA-13 which says the marking is "FF" for the new foam float?

 

[RV-7 flyer]

I'm not sure what you mean about the secondary fuel tube. Are you talking about the small diameter fuel line that goes from the carb up to the fuel pressure sender? I think most folks use SS braided flex line for that line and that is a good thing.

Or are you talking about the primer line that goes from the primer solenoid on the firewall up to the first two cyls?

Looking up the throat of the carb there is a small brass tube that runs up to where the discharge nozzle is located. The A&P said it carries "secondary" fuel, I don't know the exact name for this small tube. But it is a little loose. I think I just need a reputable repair facility to look at it. Any suggestion would be greatly appreciated.
Joe B.

 

[LifeofReiley]

I would exchange it with a reman and be done... too many shady carb shops out there for me!

 

[rvbuilder2002]

Looking up the throat of the carb there is a small brass tube that runs up to where the discharge nozzle is located. The A&P said it carries "secondary" fuel, I don't know the exact name for this small tube. But it is a little loose. I think I just need a reputable repair facility to look at it. Any suggestion would be greatly appreciated.
Joe B.

It's actually the discharge nozzle for the accelerator pump. He's right, it should not be loose. I think it is pressed in, not brazed. Their have been instances of them falling out and jamming the throttle butterfly.
The MA4SPA carb. is not very complicated. If you can find an experienced local A&P familiar with working on them he should be able to do what you need.

 

[hngrflyr]

Hmm - Does a single F mean that the metal float has been replaced with the 'old' plastic float? If so, does that mean that he still need MSA-13 which says the marking is "FF" for the new foam float?

My bad! My carburetor is stamped "MF" for the float AD and "V" for the venturi AD. I don't know anything about a new foam float.

I've had my MA-4 SPA apart. It is the simplest carburetor they could make. The shops try to make a big mystery about them and charge you $700 to replace about six parts.