Marvel Carburetor Jets

Background: Standard Jets for Marvel "VB" Carburetors are specified

in the book that Pete so generously shared as follows:

High Speed Jet P/N 49-140-D-28

or 49-160-D-28

Intermediate HS Jet P/N 49-220-E-24

or 49-180-E-24

(the reason for the "or" is that Marvel made a change mid-run to get

better performance, I suppose)

Now: According to the Marvel book (P 13), jets should be changed for

high altitude operation. We already knew that and Geoff suggested a

real good way to do that with wire hanging into the opening of the


Marvel's suggestion for High Altitude operation is to use the

following jets:

High Speed Jet P/N 49-130-D-28

Intermediate HS Jet 49-170-E-24

Question: Does the second number in the part number indicate the jet

size? For instance, in a 49-130-D-28, is the jet size .013"? That

sure would stand to reason as far as I am concerned. If so, this

gives me some indication of (1) what I have and (2) what I need to do.

Thanks for enduring all of this and for your responses.

This discussion has been closed.