Author Topic: Choke pull off bleed down time  (Read 1963 times)

My68SS

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Choke pull off bleed down time
« on: January 19, 2008, 02:25:18 AM »
Hi all, the genuine choke pull off for a 4MV quadrajet [the plastic body type of pull off] has a small brass plug with a fine hole in it in the air pipe connection, to control the bleed down time and hence the opening rate of the secondary air valves.
The bleed time when operated by hand is about 3 secs from fully depressed to fully extended.
The fuelmiser part does not have any bleed down restrictor and the arm pops out in about 1/2 a sec, causing severe engine bog.
Would be interested to hear other ppls thoughts on this issue.
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

JohnZ

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Re: Choke pull off bleed down time
« Reply #1 on: January 19, 2008, 06:02:11 PM »
What does the choke pull-off have to do with the opening rate of the secondaries? They're completely separate - the choke pull-off just opens the choke blade slightly as soon as the cold engine starts.
'69 Z/28
Fathom Green
CRG

My68SS

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Re: Choke pull off bleed down time
« Reply #2 on: January 20, 2008, 02:38:21 AM »
Hi John, I should have mentioned that I'm refering to the post '66 units [or thereabouts] were the vacuum break was given the job of also controlling the secondary air valves.
What you say is quite correct for earlier units which used the 'dashpot piston' design to control the air valves.
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55