Zenith carb question

[Guest zenith question]

Hi All,

 

I am new here.

Recently I bought an old BIG Zenith carb on Ebay.

http://www.ebay.nl/itm/261985143007?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

The bore is 2.16 inches.

I cannot find any reference about the type nor truck it is supposed to have come from.

 

I figured out its working apart from the extra assembly on the other side of the trottle.

When the trottle is opened beyond a certain angle a lever lifts a needle.

What is it for? How to adjust?

 

Any help highly appreciated

 

Is this the wrong forum, please point me the way to the right one.

 

Thanks

 

Lex

Edited August 24, 2015 by zenith question (see edit history)

[carbking]

The piece in question is called by a number of different terms, depending on who (or whom) is doing the calling. It may be called an economiser valve or a power valve.

 

The purpose of the valve is to augment the fuel supplied by the main metering jet at higher RPM.

 

The valve is normally closed, and fuel flows through the main metering jet. When the valve is lifted, an additional amount of fuel is merged with the fuel from the main metering jet.

 

Jon.