Carb. Jet Question

[Jerry McConnell]

I am reassembling my Zenith carburetor for my 1931, following the instructions in Les Andrews book. It mentions "Set jets to the narrowest point into the Venturi". The Cap Jet protrudes a half inch above the Main jet. Am I supposed to trim the Cap Jet? Jerry

[Gary WA]

no- here are the measurements for the jets.

[Marshall V. Daut]

It may be that the idle and cap jets have been switched. I've seen this before, and yet the engine still ran. The shorter of the two is the cap jet, while the longer one is the idle jet. They both have the same thread size, so they can easily be switched. When the main and cap jets are in place, there should be a very slight height difference between them to compensate for the angle that the engine sits. When the carb is mounted to the manifold flange, the jets are more or less about at equal heights. Make sure both of them have a concave (dipped inwardly) tip so that gasoline doesn't drip out of them. Many repo jets are simply cut flush across the tops, so weeping gas is a problem. The idle jet doesn't take a gasket, by the way.
Marshall

[jm29henry]

if you can find original jets the best combo that works for me are as follows (air idle #11) (compensator jet #19) (cap jet #20) (main jet #20) please make shure all old gasket are removed so that the jets are set at the right height also make shure that the float is level l and about 1"from the casting to the bottom of the float or a1"&1/2"to the middle of the float.I have rebuilt several carb and my carb run great please also make shure that all of your passages are clear.

[Jerry McConnell]

Thanks for the advise. Jerry

[Jerry McConnell]

Sponsored Links (Register now to hide all advertisements)

Marshall, Your comment pointed out the problem. I was putting the carb. back together the way it came appart; the jets were switched. Thanks Jerry