S10 Has flatspot when secondaries open, bogs down a little bit on hills

1983 CHEVROLET S-10
234,000 MILES
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IRONTIRES
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Im having issues with my 1983 2.8L, when you floor it, there's a flat-spot where the engine isn't running for like 3 seconds, then it picks up, still has doesn't have the power it should have, bogs down a bit

replaced most of the replaceable stuff

new fuel pump, filters, plugs, wires, distributor parts, checked EGR, clean oil, clean gas, new vacuum hoses, no leaks anywhere, replaced the coil, catalytic converter not plugged.

there is no computer in it, so there's no 02 sensors or anything.

May 2, 2012 at 3:14 PM
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FIXITMR
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is that a carburetor?
May 2, 2012 at 3:31 PM
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IRONTIRES
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Yes sorry, new Holly II carb 2BBL
May 2, 2012 at 3:40 PM
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FIXITMR
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vacuum or electronic advance?
May 2, 2012 at 3:43 PM
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IRONTIRES
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Vacuum
May 2, 2012 at 3:43 PM
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FIXITMR
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vacuum or mechanical secondary?
May 2, 2012 at 3:47 PM
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IRONTIRES
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vacuum i believe
May 2, 2012 at 3:50 PM
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FIXITMR
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does it do it in neutral or just under load?
May 2, 2012 at 4:10 PM
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IRONTIRES
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both
May 2, 2012 at 4:13 PM
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FIXITMR
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did problem start with new carb?
May 2, 2012 at 4:13 PM
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IRONTIRES
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yes, about a year after
May 2, 2012 at 4:15 PM
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FIXITMR
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is carb accellerator pump working ok? does it have an enrichment circuit?
May 2, 2012 at 4:17 PM
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FIXITMR
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is your timing advancing ok? is it vacuum advance or retard?
May 2, 2012 at 4:18 PM
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IRONTIRES
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i have to pump the gas about 20-25 times before it will start at first, and the timing was spot on last time i checked
May 2, 2012 at 4:25 PM
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ASEMASTER6371
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the carb is definitely your issue. you need to check the power valve which is a very common failure on holleys.

Roy
May 2, 2012 at 4:42 PM
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FIXITMR
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is choke auto or manual?
May 2, 2012 at 4:43 PM
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FIXITMR
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power valve is the enrichment i mentioned. starting issue sounds like choke related as long a fuel level in bowls is fine.
May 2, 2012 at 4:44 PM
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IRONTIRES
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its supposed to be a automatic choke, but i have to manually set it and move it around to either choke it, or allow the secondaries to open, wheres the power valve?
May 2, 2012 at 4:45 PM
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IRONTIRES
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and how would i check it/fix it
May 2, 2012 at 5:01 PM
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FIXITMR
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is choke electric? was carb BRAND new and did choke work for a while?
May 2, 2012 at 5:05 PM
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IRONTIRES
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i dont think the automatic choke ever worked, i think it was a reman carb from kragen (o'rileys
May 2, 2012 at 5:15 PM
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FIXITMR
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as i remember the PV is in the bottom of primary bowl large nut thing unscrews to remove.
May 2, 2012 at 5:16 PM
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FIXITMR
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look here. http://www.holley.com/types/Power%20Valves.asp
May 2, 2012 at 5:17 PM
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IRONTIRES
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maybe its clogged up with carbon? a few months ago i took it apart and cleaned out a crapload of carbon
May 2, 2012 at 5:20 PM
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IRONTIRES
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just the top of it though
May 2, 2012 at 5:21 PM
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IRONTIRES
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also, if any vacuum hoses are hooked wrong, would it cause it to not work right? i believe i have them all hooked up right, does anyone have a diagram i could follow?
May 2, 2012 at 5:23 PM
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IRONTIRES
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do you know which connection allows it to open?
May 2, 2012 at 5:24 PM
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FIXITMR
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i know carbon always screwed up the quadrajet power valves. rig up a manual choke pull rod in cab to help with starting.
May 2, 2012 at 5:25 PM
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IRONTIRES
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yeah i was going to go buy the cable setup from the auto parts store, you said the power valve was operated by vacuum? is there a way i could check it without opening the carb?
May 2, 2012 at 5:30 PM
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IRONTIRES
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i found http://www.holley.com/data/TechService/Technical/power_valves.pdf
im checking it out
May 2, 2012 at 5:46 PM
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IRONTIRES
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i cant seem to find the idle mixture screw on mine, that pdf file said i could test it by screwing it all the way in, and if the engine dies its working
May 2, 2012 at 6:21 PM
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ASEMASTER6371
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the idle screws on control idle, not anything off idle.

Roy
May 2, 2012 at 6:23 PM
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FIXITMR
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power valve should work off carb base plate not any external connections.
May 4, 2012 at 12:07 PM
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