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Old 06-18-2003, 09:11 AM   #1
TC70C10
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Join Date: Nov 2001
Location: Harvest, AL 35749
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Help the fumes are killin me..!

I've read all the posts on tuning a q-jet on this site but right now I don't know where to go next.
rebuilt 305 installed 6 months ago
Original Q-jet that was rebuilt about 6 months ago. I can't seem to get rid of the "rich" smelling exhaust and smoke(black/blueish). I set the timing and idle and back out the screws to highest vacuum reading. I'm steady at about 17 in/Hg. I took air horn off last night and checked float setting. It actually appeared a little low so I raised it to the 15/16 in(stock setting).

I also noticed when I put the vac line back on vac advance timing retards to about 12 or 13 BTC. This goes back to the question of whether the vac advance should have vacuum at idle. I've been through the vac lines and routing appears correct. All new hoses.

I'm going to pull a compression test tonite.

Any ideas will be greatly appreciated
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1981 K5 Blazer 305, 4spd, 4x4, 4" Lift, custom bumpers, Warn 9.5 Ti Winch
1995 T10 Blazer 4.3L 4x4 (Son's)
2004 GMC Envoy 4.2L 2WD
2005 GMC Sierra Crew Cab Z71 4x4 5.3L
240 Fun Finder Travel Trailer

Harvest, AL 35749
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Old 06-18-2003, 09:53 AM   #2
lngbed71
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I don't think you need vacuum advance at idle. When the motor spins up under load, the vacuum advance port pulls the armature for the advance on the distributor. Try relocating the advance line to another port on the carb.
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