I was breaking down a set of IDF 40 to rebuild, and I had my camera on hand, so I decided to just take pictures of where all the jets were usually found. I know it took me a LONG time to find them the first time I tore a set of carbs down.

And, yes, these parts are FILTHY. As I said, I'm tearing them down for a rebuild.

ON TO THE PICS!

The Main Jet Stack, exploded (2 stacks per carb):


Main Gas Jet


Emulsion Tube


Main Air Correction (sorry it is blurry )



Inlet Valve (The Brass nut looking thing at the bottom of your carb fuel bowl - 1 per carb):


Idle Jet (located on the outside of the car, towards the top, just above the pump diaphram - 2 per carb)


Pump Jet (Located on top of the carb, under the carb cover - 2 per carb)


Main Venturi (2 per carb)


Aux Venturi (2 per carb)


I hope that this helps.
Any hints on making the title easier to search on?
Zach

It's a one stop tech article... which is where it should go. Weber jet identification guide. Nice close ups and lables. Thanks for the effort!

Thanks SGB, I changed the title taking your suggestion. It was more better then mine.

Zach

Nice work Zach.

I agree with SGB, this should be moved to the tech article area

Nice pics Zach....

Now, please explain, in detail, under which conditions the various jets should be changed, either up or down in size.

-- Rob

Admins?

Y'all should move this before it sinks- o'course it would search back up with weber, jets, IDF. I guess that would about cover the searches...

Jets should be changed in size everytime you increase the displacement of the engine, Go to a bigger badder header, Carb changes in venturi sizes

going from 100 degrees to 30 degrees outside air temp.

Zach - I can't read the size on the idle jet picture. What are you running? What do you recommend (1.8L)?

Oh, these pictures are just to show the noob IDF rebuilder where their jetting is stamped, and how some of the tricky bits go together.

The jetting that I will be using for my 2056 (and its not what is pictured - I just had my camera handy when I took the carbs apart) would not work for your 1.8.

But, the pictured idle jets are 50s, and are probably what you would want for your 1.8.

Zach

The number relates to orifice size, but jets can be drilled to make the hole bigger. So if you've got unknown jets, you must measure them to be absolutely sure they are what they say they are.

Also, the jet you have marked as the 'inlet valve' at the bottom of the fuel bowl, is also an accelerator pump bleed off jet. When the accel pump is pressurized (squirting) the fuel is forced down three paths. Paths 1 & 2 are the nozzles in the throat (labelled 'Pump Jet' above). Path 3 is the accelerator pump bleed off jet. By changing the size of this jet you can control the quantity of fuel squirted out of the accel pump jets. By making the accel pump bleed off jet bigger you allow more fuel back into the float bowl, and therefor less fuel is squirted into the throats. And if this jet gets plugged, you get LOTS of fuel out the accel pump jets.

Bigger = Less Squirt
Smaller = More Squirt

This is the bleed off hole. Also, this jet/inlet is a ball valve and when you have it out you should be able to hear the ball rattling inside when you shake it.

I know this is a 14 year old thread, but I wanted to thank @VaccaRabite for it as it was a huge help to me today.

Excellent! I'm glad you found it helpful.

Zach

Glad for the revival. I had not seen this one.