WEBER Expertise needed - inlet popping related to drilling lead balls?
 

Weber experts needed.

I recently rebuilt my 40IDA's and am having some issues.

During the rebuild I drilled out all of the lead balls used to plug cross drillings (3 on the front with the jets, 3 on the top of the main body one from each set plugging the same pair of intersecting passages) and re-plugged with fresh balls.

(I have used web images and tried to indicate the location of one of each three balls below - lower arrow may not be pointing correctly as I cannot see the ball in this view)

I now have an issue where it misses on #2 a lot and I think the loud inlet popping is also coming from that cylinder. That is also associated with the specific lead balls I am concerned with.

If, in the drilling and re-plugging of this particular circuit in the center of this carb I either partially blocked this circuit or air is leaking in past the balls would it cause this?

Thanks
Sam


http://forums.pelicanparts.com/uploa...1400455719.jpg

http://forums.pelicanparts.com/uploa...1400455731.jpg

Misfire
 

I should add that cylinder only has issues at idle / transition, when at full throttle it runs fine.

Balls
 

Better shot of upper ball I replaced and am concerned with relating to #2.

http://forums.pelicanparts.com/uploa...1400456209.jpg

OK, last piece of the puzzle.
I am pretty sure it is #2 popping and the O'ring from that cylinder extruded out and around the head of the idle jet holder. Would #2 inlet popping create pressure to do this? (I assume yes)

What happened to your floats? They look like they have been crushed.

Floats
 

Those are web pics I found to try and show the lead balls without tearing down my carbs YET again.......don't panic, my floats look a little better!

I'm not an expert.

But you suspect the plug might be affecting cylinder two. I think any plug that does not seal either leaks fuel or air or both.

Unfortunately, you probably do have to take the carb apart. Nothing I say will change your data. Unless you open up the idle screw and compensate, the popping won't go away. But do you really want to compensate, or fix it?

A mechanic's stethoscope with the metal probe removed may help to isolate #2 as the popping cyl; just hold the open tube close to the intake and check each cyl individually.

On mine I put a coupler in so I can have a nice long inspection tube vs. the shorty which would result from just pulling the probe and diaphragm off.

Go slow- it could be loud.

That is an example of what happens when an compressed air nozzle is used on the carb itself where the idle jet screws in..I have seen this before.

You might call Paul at Performance Oriented or he might see your post and reply..outstanding person to talk with...very helpful considering this is how he makes his income.

http://performanceoriented.com/

You will need to completely re-sync; did you do this? Have you balanced the barrels using a flow meter? Did you set the float levels? Lots of missing info.

OK, just to reiterate. Those floats are not mine - just an example.

The carbs were thoroughly cleaned, rebuilt, resynched, the float height and pump volume set and mixture set for each cylinder (when firing). All that is good.

My question really is specifically just what is the effect of either blockage in, or leakage into that circuit plugged by the lead balls that goes from idle circuit to emulsion tubes...