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Old 04-25-2003, 04:12 PM
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Question 350 sbc bogging

Can anyone give me an idea on why my 350 boggs when I jump on the throttle from an idle? I've cleaned the carb, checked the timing (8 degrees ATDC), cleaned the plugs and it still boggs when i floor it, after coming off of idle i have no problems with it, it just seems like the vacuum advance doesn't kick in soon enough...and i'm not too knowledgeable about vacuum advance. Any help is appreciated.

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Old 04-25-2003, 04:14 PM
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8 degree`s AFTER top dead center? if that`s where your timing is no wonder it bogs, it`s amazing it runs at all. if you meant Before top dead center, I`d say check the fuel pressure, the filter also. I`m guessing your running a 4 barrell carb, if so, then it sounds like the secondary`s are coming in too quickly and need to be adjusted.
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Old 04-25-2003, 04:20 PM
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If it isn't the timing it could also be that it is running to rich. Do you have black smoke when you jump on it?
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Old 04-25-2003, 04:22 PM
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yes 8 degrees BTDC sorry, and yes a 4bbl carter 650cc....so its probably nothing with vacuum advance
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Old 04-25-2003, 04:22 PM
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no black smoke
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Old 04-25-2003, 06:32 PM
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Make suer you have a good amount of initial fuel squirting thru from the accelerator pump, sounds like the bog is from a too small squirter, though I practically know zip about carter carbs but its worth a shot. With engine off and air cleaner off have some one mash the throttle while you observe how steady and strong the fuel shot is into the primary's good luck.
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Old 04-25-2003, 06:57 PM
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What kind of intake manifold?...Some stock manifolds don't flow too well and it could be part of the problem....GlennK
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Old 04-26-2003, 08:24 AM
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[quote]Originally posted by Gearhead70Chevy:
<strong>Can anyone give me an idea on why my 350 boggs when I jump on the throttle from an idle? I've cleaned the carb, checked the timing (8 degrees ATDC), cleaned the plugs and it still boggs when i floor it, after coming off of idle i have no problems with it, it just seems like the vacuum advance doesn't kick in soon enough...and i'm not too knowledgeable about vacuum advance. Any help is appreciated.</strong><hr></blockquote>

You will have ZERO vacuum at WOT. The vacuum advance has nothing to do with your problem. You have stated that your initial advance is actually 8 degrees BTDC. This is not enough. Look for 10-12 degrees BTDC initial and 34-38 degrees total around 2500-3000 RPM. Check and set your timing with the vacuum advance hose disconnected and plugged.

With your engine off, moved the throttle linkage slightly. You should see fuel squirting from the accelerator pump outlets immediately. If not the linkage needs to be adjusted.

[ April 26, 2003: Message edited by: Frisco ]</p>
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Old 04-26-2003, 12:19 PM
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Thanks for the tips guys.

PS... Edelbrock performer intake cam and lifters.
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Old 04-26-2003, 03:16 PM
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Mine (Q Jet) does the same thing sometimes, I was told my air valve was too loose, I adjusted it and now it doesn't really do it anymore but now it idles funny.
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