idle jet question

[Seaspot]

I am rebuilding my late model carb. When I removed the idle jet I notice that it is different from the one supplied with the Moyer kit.

The new one is very short and the old one has an "extension" tube that makes it much longer. The threads look to be the sam on each.

So my question is, do I install the new one that came with the kit, or reinstall the old one?

Here's a picture of them both. The old one is on the left, the new one is on the right.

[Seaspot]

Ouch, sorry about the picture size!

[roadnsky]

Look for a stamped NUMBER on the slotted side of the jet.
The standard fixed main jet size is 21. (See Pic)

If in doubt, I'd suggest using the MMI supplied jet.

[Seaspot]

Well, I bought the adjustable main jet to install in this carb. The jet I am asking about is the idle jet that installs near the float needle valve.

[Dave Neptune]

Idle jet

Seapot, I have done quite a few of the A-4 carbs over the years and I have seen both. The new style is just shorter, feeds the same chamber and makes no difference. The older long style jets are just more expensive to produce so Zenith stopped making them. I have orderd new jets from them and recieved both styles more than once.

Dave Neptune

[Seaspot]

Thank you Dave, that's good to know. I wasn't sure and I didn't want to have to go through this again because I put the wrong one in.

Thanks again, you really helped me out!