View single post by discogodfather
 Posted: 06-29-2020 09:57 am
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discogodfather



Joined: 09-17-2007
Location: San Francisco, California USA
Posts: 221
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 I can understand some basics in regards to Webers and Dells in that they have jets, you change them, they basically follow a rich to lean logic. Bigger mains, more fuel. In some cases bigger numbers mean leaner like with air correctors.

Never understood the emulsion tube. When you look in the Hammill Book on Webers and Dells, he tells you what most of the internet tells you, that emulsion tubes go from a kind of a rich to lean setup and you should basically start with a tube based on cylinder displacement. That led me to F2's, which ran awfully. Most books and sources seem to say that the other emulsion tubes besides F11, F16, F2, F7, etc. aren't really used and the explanation kind of "trails off".

I was just randomly searching on youtube and found this old David Vizzard lecture, and the wool is defintely being pulled from my eyes. In it, he says to turn the emulsion tube upside down and look at the holes on the tube. If there are holes up top towards the main, then your top end is leaned. Middle holes control middle mixture, low holes low end, etc. What a great insight!

Armed with that knowledge I started to compare my emulsion tube collection, F2, F3, F4, F16, F7. The tubes that worked the best in my setup was the F4, and low and behold it has holes at the top, middle, and bottom. Seems like this engine likes leaner.

Finally some basic things starting to make sense.

https://www.youtube.com/watch?v=1pkFSA_rRFI