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Author Topic:   qjet bog
Dirt Roller

Total posts: 9
posted August 06, 2001 07:55 AM
I am running a qjet carb on a 403 Olds engine in my 76 cutlass. I engine bogs when I get into the throttle. It is pretty bad almost to the point of killing the engine. Is it my accel pump or ignition timing or ?


Dirt Full Roller

Total posts: 42
posted August 06, 2001 07:43 PM
Hey BlueBomber it could be your secondary air flap is opening to soon. If it opens to quickly before the engine can handle the extra gas it will bog down. There is a adjustment on the side of the air flap. You need a allen end wrench and a small regular *****driver to adjust it. If you turn the skrew clockwise it will tighten the spring and keep the air flap from opening to fast and bogging the engine. You really want the flap to open at the exact time the engine needs the extra gas and air. The only way this can be exactly determined is with constant tinkering. Anyway that is the first thing I would check. Hope this helps 34RACING

Dirt Roller

Total posts: 12
posted August 07, 2001 12:24 PM
This last year I completely rebuilt my qjet 750. I changed a lot of stuff to increase the amount of fuel in the bowl and the amount of fuel delivered with the pump shot. If you want I can send you the details. After all the changes I still played with secondary throttle valve opening rate. Once I got that
right, I still had some bog coming off the turn. Then I made a power pistion spring change. I had 3 springs, long, medium and short. When I did the rebuild I put the medium spring in. When I made the power pistion spring change I put in the short spring and the bog went away!

Dirt Roller

Total posts: 7
posted August 08, 2001 12:56 AM
It is really important to make sure that the primary power piston/metering rod plunger is free of binding, it should operate SMOOTHLY.

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