Weber rebuild questions

[Davz912/911]

Well I'm ripping into my 40 ida's. It started with gas overflowing into #3 . I thought a float sunk on me, but after dis-assembly, the float looks fine (no gas in it). I'm thinking my float valve may have stuck. Any ideas what else could cause this? I also found the PO was running 110 mains, 45 idles, f26 emulsions and 180 airs. The PO was at 4000 feet so I figure it was set up for thin air. Sure explains my surging at low rpm.s here at sea level. I've ordered
some 125 mains and 57 idles (I know, kinda odd size, but thats what Pierce had listed, seems ok, we'll see.) I guess I'm just looking for a "that set-up should work fine comment". Any other things I should look out for during the re-build? (I've done my 48 ida's before).

Thanks in advance,

Dave

[LeafGreen]

Spontaneous overflowing is almost always debris in the needle and seat.

[ttweed]

Such a problem can be caused by the additives in modern fuel formulations as well. Read the article by Steve Weiner in the new Esses, or on his website. The relevant section:
"Some brands of fuel have been known to dissolve the interior of rubber fuel hoses!. Some of these items will need constant observation and regular replacement to prevent engine problems.... For example, a leaking rubber-tipped float needle in a Weber-Carbureted 911 can fill a cylinder with fuel causing hydro-lock and result in engine damage as well as a major fire hazard."

It is less than comforting to think that your last fuel fill could be dissolving your fuel lines or your float needle tip.

TT

[Davz912/911]

I remember hearing that, something to do with less smog, a gas formulation with mtbe. But didn't they get rid of that stuff? Once the enviromentalists heard it was destroying the water table didn't they phase it out?

[Davz912/911]

Well, after rebuilding carbs, and installing new jets, the car ran like crap. White smoke billowing out of the exhaust, it was way to rich.Poor throttle response, no\low power. I put the old jets back in and it runs and pulls fine.
I went ahead and balanced and dialed them in with the old jets. I'm running NGK bp7es plugs, are they to cold? The "new" jets, that don't run, are 57 idles, 125 mains, it came with f26 emulsions and 180 airs, I left the last two in. Any ideas on why the "new" jets performed so poorly?

Thanks,

Dave

I set the floats dead nuts with a digital dial indicator, fwiw