Attn. Lars
Thread Starter
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
Attn. Lars
I have a 454 in the shop with a Q-Jet #7040502 (original to a 70 350-300). What the problem is I can't get the idle mixture rich enough. Any suggestions? No apparent vacuum leaks.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
The following items will affect idle lean condition:
Vacuum leak
Incorrect jets and/or rods
Low float
Low set power piston height (or piston modified by cutting tang)
Warped airhorn (leaking air into transfer passages)
Incorrect base gasket
Incorrect throttle plate gasket
Altered idle air bleed system (common on commecial rebuilt carbs)
Secondary throttle plates not fully closed
Let me know if you need more ideas.
Lars
Vacuum leak
Incorrect jets and/or rods
Low float
Low set power piston height (or piston modified by cutting tang)
Warped airhorn (leaking air into transfer passages)
Incorrect base gasket
Incorrect throttle plate gasket
Altered idle air bleed system (common on commecial rebuilt carbs)
Secondary throttle plates not fully closed
Let me know if you need more ideas.
Lars
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
Originally Posted by big_G
Thanks Lars....I think I'll order the correct app. carb., as this one (off a 350) is the smaller version..., I assume big-blocks got the larger version?
You probably need to put bigger jets in.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by big_G
Thanks Lars....I think I'll order the correct app. carb., as this one (off a 350) is the smaller version..., I assume big-blocks got the larger version?
