TheSamba.com :: View topic

Sat Aug 16, 2008 11:01 pm

So, yet another carburetor problem I think. Single 44mm Weber IDF

You can see my other thread here.
http://www.thesamba.com/vw/forum/viewtopic.php?t=312592

After I got the carb back together, and everything installed, started it up, ran PERFECT with the choke off... After a little bit of driving around, ~10 miles, it starts to misfire. Come to find out that the 3&4 cylinders are not firing at all, flooded with gas. Take the plugs out, put new ones in, runs good for about 10 seconds then floods 3&4 again. Always 3&4 that flood right away. It seems like it is sucking in massive amounts of gas when it runs from just that barrel.

Spark is good
Compression is good
Timing is on

I have no idea.. Should I take the carb apart again? Could it be some kind of vacuum leak?

Sat Aug 16, 2008 11:39 pm

Fuel psi?
Float setting?
Bad needle and seat?
Bad float?
Incorrect plug gap?

Sun Aug 17, 2008 11:26 am

Bump. Tore the carb apart again... Cleaned it, checked it.. All ok.. Put it back on, same thing, but it seems to pickup the 2 cylinders @ around 3000rpms.

Fuel pressure is spot on.

Carb has under 500 miles on it, along with the engine, so I imagine it wouldn't be worn out.

Float is good.

Plug gap is correct

Sun Aug 17, 2008 1:44 pm

Sounds like the float height is off or main stack isnt tight

Sun Aug 17, 2008 4:08 pm

Vacuum leak would not cause rich condition. I think your idle circuit is getting plugged up.

Sun Aug 17, 2008 6:44 pm

Is it one of the new IMPI carbs?

Sun Aug 17, 2008 7:36 pm

How are you determining that the cylinders are "flooding out"? It sounds like a plugged idle jet to me too.

Sun Aug 17, 2008 9:32 pm

lostinbaja wrote: How are you determining that the cylinders are "flooding out"? It sounds like a plugged idle jet to me too.

Yeah, It is not getting enough gas on that side.. Only thing that gives it enough gas is the accelerator pump... I sprayed carb cleaner in that barrel with it running at idle and the 3&4 cylinders picked up...

How can it be plugged.. I thoroughly cleaned the carb with carb cleaner, and then blasted it out with a little compressed air.. I couldn't find any passages that air/carb cleaner wouldn't go through..

Dunno, this thing is driving me crazy.

BTW: it is not an IMPI carb, I think it said made in Spain on it.

Mon Aug 18, 2008 4:42 am

How many turns out is the 1-2 side mixture screw? I'd set the 3-4 one to about the same. Then start it.. unscrew the idle jet slightly and see if it starts to pick up. If it does, you have a plugged jet. If it doesn't, you have some blockage between the jet and the float bowl.