Carter AVS float height

[TrackPack]

Rebuilding a swap meet 4615 AVS for my road runner. On disassembly I see that it has the small floats and are set at 7/32", while my 4640 with large floats is also set at 7/32". What's the correct setting on these small float carbs? Seems like a lot of conflicting information in my searches!

 

[493 Mike]

Rebuilding a swap meet 4615 AVS for my road runner. On disassembly I see that it has the small floats and are set at 7/32", while my 4640 with large floats is also set at 7/32". What's the correct setting on these small float carbs? Seems like a lot of conflicting information in my searches!

My guess is 7/32"!
Doesn't the instruction sheet have that info? I have been rebuilding carbs since the late 60s and all the kits I used had that info.
Mike

 

[TrackPack]

My guess is 7/32"!
Doesn't the instruction sheet have that info? I have been rebuilding carbs since the late 60s and all the kits I used had that info.
Mike

I have a sheet from a Hygrade kit. All of the settings for the 383 are 5/16 level and 13/16 drop. Settings for 440's and 340's are 7/32 and 23/32. Makes me wonder if the info is legit.

 

[Vaanth]

The float setting for the 4615S AVS is 5/16". Float drop is 23/32".

The float setting for the 4640S AVS is 7/32". Float drop is 23/32".

Edit: some specification sources list 13/16" float drop for the 4615S. The factory service manual specifies 1/2" float drop for the 4615S.

 

[TrackPack]

The float setting for the 4615S AVS is 5/16". Float drop is 23/32".

The float setting for the 4640S AVS is 7/32". Float drop is 23/32".

Any idea why the 340 settings are different than the 383? Basically the same carb.

 

[Vaanth]

Any idea why the 340 settings are different than the 383? Basically the same carb.

Differences in the specifications from Chrysler and Carter are based on their determinations of combination and tuning variances with regard to the application. Why all the specific setting differences are present is likely lost in their engineering history although float height can affect mixture in some instances. There is also the float size difference to consider which is a difference for the 4615S 383 carburetor versus the 4640S 440 carburetor. The AVS carburetors used on the 340, 383, and 440 are indeed basically similar, but not necessarily the exact same, else they would all have the same number, yet still possibly with different setting specifications per application.

 

[TrackPack]

Thanks.
I guess I assumed that the 383 and 340's would both have the small floats. I'll go with the more conservative 5/16 level.

 

[Geoff 2]

A fuel pump with a different pressure will change the fuel level in the bowls. More pressure, higher fuel level. The higher fuel level will provide a slightly richer mixture.
So a fuel pump with, say a higher output pressure may require a larger float adjustment dimension to maintain the desired fuel level. A vehicle designed for high altitude areas require a leaner mixture than sea level, so this could be obtained via float level adjustment.
Carter provided a chart for setting float level based on pressure & n/seat size.