Weber Needle Question

[fnmag58]

I recently purchased two Weber rebuilding kits and they came with the 1.50 mm diameter needle and seats. During the disassembly, I discovered that mine have the 1.75mm set up. I don't see much of a difference besides the hole diameter in the brass seat. Does it really make a difference for a 1.6 L crossflow? Will the smaller hole allow sufficient fuel flow? Can I just take a drill bit and drill them out to the 1.75mm diameter? The company that I bought them from won't take them back since I opened the packages--of course, you couldn't tell what size they were since they were in a tiny plastic tube.

 

 

 

Thanks for the help.

 

 

 

 

[stevet]

Sal,

 

 

 

Can't help with your question, but I do have an old set of main jets off Weber 40's if you want them. They're 1.2mm, so probably too small, but they're jst sitting here doing nothing...

 

 

 

Steve.

[lowflyer]

If the old ones aren't leaking, why replace them?

 

 

 

If you do install the smaller ones, it will be easy to tell if they are too small. At full throttle, especially under a load such as going up a hill, the car will "run out of gas" from the floats running dry.

 

 

 

If you don't have the problem then they are proabably large enough.

[fnmag58]

Lowflyer,

 

Thanks for the input. The Webers for my car have been sitting for over 5 years and really need a complete rebuild. The needle/seats were stuck closed when I disassembled them. I agree with the fuel starvation issue. I'm just going to order the correct ones and not worry about it.

 

 

 

Thanks again,

 

Sal

[lowflyer]

One thought... be sure to use the latest carb insulator blocks when you mount them up. The last ones I had were aluminum castings with grooves to accept rubber O-rings.

 

 

 

Probably the most common problem with the dual Weber set up is vacuum leaks around the blocks. Don't overtighten them, and use locking nuts (not the nylon ones, as the engine heat tends to make them fall apart).

 

 

 

Good luck and hollar if I can be of any help. I've played with Webers for about 20 years now.