Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - Carb vacuum diagram
View Single Post
  #19 (permalink)  
Old 04-03-2007, 01:41 PM
F-BIRD'88's Avatar
F-BIRD'88 F-BIRD'88 is offline
Yada Yada Yada
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,284
Wiki Edits: 0

Thanks: 5
Thanked 399 Times in 393 Posts
Originally Posted by 2_Late_I_Won
Well it's a 2 speed powerglide and I'm already in the upper rpm's when it starts to open. I would say around 4,000-5,000 rpm. Around 4-5K rpm I'm already doing close to 50 in first gear. ( I know I have really tall gears) But I was hoping with the other two barrels opening earlier. That that would help me off the line more. With a white spring ( the lightest) I would expect them to start to come on around say 2,500 rpm or so. I don't know maybe this is right where they are supposed to come on at.
What you are feeling in the seat of your pants while driving is not the secondaries starting to open.
They are actually opening right off idle (with the white spring) and opening too, too fast.
When they open too fast the engine airflow thru the carb is not fast enough. The carb cannot meter the fuel. (lean bog,soft acceleration). Then once the engine airflow ( speed) thru the carb catches up, the fuel flows properly and makes power. You feel that as a power surge.
Remove and reinspect the diapharm and diaphram housing seal for a leak. Use the thumb over the holes method.
make sure the little check ball is in the housing vac passage. Try a stiffer med tension spring. Try raising the float level a little on the sec side. (faster fuel metering reaction)
You really need to switch to a secondary metering block with jets and rear sec jet extensions. The fuel in the sec bowl gets pulled away from the sec jets on acceleration.
Reply With Quote