Author Topic: bog at WOT  (Read 2503 times)

Offline 70f400

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bog at WOT
« on: August 12, 2015, 02:26:51 PM »
1705 7262 carb rebuilt with Cliff's parts. 73 jets, Pr rods 44, idle tubes .039, idle down channel .059, by pass air .110

455 ra4 cam, 9.75/1 compression, auto with 3.42 gears, intank fuel pump with return regulator 7 psi to carb

I can not get rid of the bog when the secondaries open.  I have adjusted the air flap spring from 3/4 turns to almost 2 turns.  This just changes the rpm that the secondaries open at.  from a dead or rolling stop when I accelerate hard it just stumbles and bogs until I get above 3000 rpm.  The  engine idles great and works great for just driving around.  I do not feel like the choke pull of is working to slow down the rate of the air flap opening.  Is there a way to adjust this or is the new choke pull off possibly bad.  Or is there something else I should check.  I borrowed a Q jet ( Jet performance stage 2) from a friend and other than it being a 750 and being a side inlet,  It works much better. On this borrowed carb I can feel resistance from the choke pull off when the car is running and I push on the secondary air flap I dont on mine.  My friend ask me not to adjust anything on it except the idle screws, as it is set up for his car.  Any thoughts?

Offline Frank400

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Re: bog at WOT
« Reply #1 on: August 12, 2015, 06:11:56 PM »
You mean that you can move your secondary air valve at idle ?  You should not be able to at idle since the choke pull-off is holding it, because of the vacuum.  When you nail it, there is no more vacuum so the choke pull-off "looses it's grip" on the secondary air valve, sort of, allowing it to open. 

 

Offline 70f400

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Re: bog at WOT
« Reply #2 on: August 13, 2015, 08:00:25 PM »
Yes it is pretty easy to overcome the pull off.  Vacuum is 14-15  at idle.

Offline Cliff Ruggles

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Re: bog at WOT
« Reply #3 on: August 14, 2015, 03:30:56 AM »
Assuming that you installed a new secondary cam/spring check the pull-off to make sure it's holding vacuum and that the release time isn't way to quick or way too slow.  It should be around 1.5-2 seconds......Cliff

Offline 70f400

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Re: bog at WOT
« Reply #4 on: August 14, 2015, 03:45:39 PM »
Float was set at 3/16 changed to .275.  Secondary metering rod hanger bent badly.  Fixed and performs well.

Offline Cliff Ruggles

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Re: bog at WOT
« Reply #5 on: August 22, 2015, 12:58:08 PM »
Good news.  I set those carburetors at 9/32" for float height, and have never had the first issue one with any of them.....Cliff