Sanity check on 7040507 rebuild, please...

[Sonny]

Hello -- would anyone be able to confirm if the following measurements reflect the factory specification for a model 7040507?

upper idle airbleed: 0.078 in air horn
lower idle airbleed: 0.070
main airbleed(s): 0.110 in both main body and air horn
idle bypass air: 0.110
idle tubes orifice: 0.029
idle down channel cup: 0.046
main jet: 74
primary metering rod: 44B
fuel inlet seat diameter: 0.130

To me the jet and air bleed sizes say it is a very lean unit and will need some work to fit one of the recipes in Cliffs book.

Thanks in advance for your help

[carmantx]

I show it had 76 jets original with 44 rods.
Idle bleeds and mains seem correct.
Idle tubes would have been .038 and DCR at .050-.052
According to my notes on this specific code.

Yes, these were set up lean and that is a California emissions carb as well.

[Cliff Ruggles]

The upper idle airbleeds should be in the main body just above the DCR's, not in the airhorn.

The idle tubes are larger than .029" as mentioned.

A 74 jet and 44B rod would be a very lean calibration for one of those.....Cliff

[Sonny]

Thank you CarmanTX and Cliff. Noting the upper idle air bleed in the air Horn was my mistake. It is in the main body. I will recheck my measurements on the idle tubes. There are 76 jets in the spare parts found with the carb. Also found several power piston springs. The one in the carb appears like it was shortened.

[Sonny]

The idle tubes are larger than .029" as mentioned.

Remeasured the idle tubes at 0.035

There is a pair of 78 jets with the carb. I will start there. Plan to follow recipe 3.

A closer inspection of he plastic fuel bowl insert revealed a cracked and seems fragile. Are new replacements available?

[Cliff Ruggles]

No new ones out there that I know of.  We have nice used ones in spare parts and actually sell quite a few of them......Cliff

[Sonny]

I will add that to my parts list.