testing jets

[160B]

Originally Posted by redmodelt

RE: 2. the length of the hole.
Please expand on that in relationship to the jets in a Model A carburetor.

Original jets are a certain length, but the inside diameter is not the same over the entire length.

At the tip of the jet there is an orifice, smaller diameter sized to deliver the correct amount of fluid. This orifice is say 1/32” long at say a # 63 drill size.

Now when you solder the tip closed you cannot control the amount of solder that flows into the tip of the jet. So let’s say after soldering you now have to drill a # 63 size hole through let’s say 3/32” length of solder. This jet now has the same size orifice of # 63 drill but since the orifice is now 3/32" long the flow will be reduced.

Also the entrance into the orifice is not the same gentle curve due to the results of soldering, so this will also reduce the flow because you have changed the entrance characteristics of the orifice.

I will upload photos when I resolve a missing security token that does not allow me to upload photos