I'm at my wits end - My MPG is 10 down from 15 when I had an old leaky Holley 1850. I've jetted it down twice from the original 70/80 to 68/78, then 66/78 and I think it still runs rich and it smokes at WOT. I also changed squirters from 31 to 25 which decreased the smoke at WOT to some degree. If I go to 64/76 I may have to up the squirter (?). Is 64/76 way to lean for a 350?

I also have a fumes problem in the car. Whenever I drive in stop and go (vs. highway) I end up smelling like fumes. For some time I thought this was exhaust leaking into the cabin (header leaks) but now I wonder if a way-rich condition is part of the problem. I've got to get this fixed it is my daily driver and I'm sure this isn't healthy. I am trying to figure out where the fumes are coming in to try and seal that as well.

More details on the Malibu here:
http://personal.atl.bellsouth.net/at...dh/webpage.htm

Thanks for the help,
Chris

 

check your float level, and change the power valve. the Demons have blowout protection in them, but it still happens occasionally. Float level should match with the bottom line of the three etched on the bowl. If you have a big cam, check your vacuum at idle. Set your idle speed screws correctlt, and if you have low vacuum, you may need to put a different level power valve in it. Take your best vacuum at idle, divide by two, and add .5. This will give you a good starting point.

 

I done this one. Lower the float and keep going lower on the jets untill you spark plugs start to look light tan color. I also changed the idle feed orifices in the primary venturies and in the primary metering block. They just seem to set these carbs up really rich.

BearTracks

 

An odd development - the other night while checking all my hose connections (to rule
those out) the vacuum cap came off of the vacuum T at the back of the intake manifold. This T has the large hose running to my PCV and the small tube is capped as it isn't needed (no more TH350) The cap was brittle and wouldn't stay on so I had to leave it off (it's right next to where the big vacuum connection comes off the back of the carb and is hard to reach).

My idle speed went up (expected) - the odd thing is the gassy smell was diminished. Maybe it's not my jetting (currently 66/76) that's off it's my idle settings. This would make sense because the problem is at it's worst in a lot of stop-n-go driving: idling. This addition of unmetered air has leaned my idle - and maybe a leaner idle is what is needed.

I was at 1 1/4 turns out on all 4 idle screws and have turned them in to only 1 full turn out to see what happens. I'm trying to avoid messing with the idle air bleeds until it's my only hope. I also replaced the missing vacuum cap.

Thanks for the ideas so far - I'm investigating ALL possible solutions,
Chris Lindh

 

I've got the same problem... only I have a Holley... If/when you figure it out, post it, I'll do the same!

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

So far the turning the idle screws in has removed some of the gassy smell. I also resealed my a/c box (this is on a Malibu remember) and I'm hoping that will help as well. The carb still has 66/76 jets in it at this time. I think my header leaks are contributing to the problem - just now because the mixture isn't so rich the leaked exhaust isn't as offensive. Dynomax headers are crap.

Chris