Lean or rich?

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Lean or rich?

Postby Ruggage » Fri Feb 13, 2009 7:00 pm

Lets say my 305 is idling, I put my hand over the carb inlet (reducing air intake volume) and the idle
noticelably increases rpm, is the fuel mixture too rich or too lean?

The motor also bogs down under load & increased rpm's.

Thanks,
Glen
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Re: Lean or rich?

Postby spyder_xlch » Fri Feb 13, 2009 7:05 pm

Putting your hand over the carb (just like closeing the choke) richens the mixture. Does it smell rich when you do this? It might be your carb is dirty or sucking air. I'd say it's running lean right now but you have to figure out why.
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Re: Lean or rich?

Postby cjbiagi » Fri Feb 13, 2009 7:19 pm

Assuming the carb is jetted properly it sounds like a classic vacuum leak. Check all of your hoses, carb to manifold bolts and gasket, intake manifold gasket etc. Could also be a leaky brake booster ( any brake problems?) or anything else that is vacuum operated.
Clyde.........75 Monza 2+2
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Re: Lean or rich?

Postby chevyart » Fri Feb 13, 2009 10:56 pm

hey CJ you are right on the money with your post keep up the good work chevy art
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Re: Lean or rich?

Postby NixVegaGT » Sat Feb 14, 2009 10:31 am

If it's a qjet just be careful not to tighten the carb bolts too tight. Especially on the bowl cover portion. Lot's of warped qjets because guys tightened them down trying to fix a vacuum leak and made it a lot worse. You may have a bad accelerator pump too.
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