New year, new things to fix

In todays episode I want to figure out why the carb bogs down when I tap the throttle off idle.

It happens both when warm and cold, and it is also noticable if I tap the throttle while cruising.

I shot some footage with my potato-phone, so bear with me on the quality. I was going to use a better camera, but it was out of battery at the time. Hopefully you'll be able to spot the symptoms anyways, and maybe we'll be able to fix it. If not I've already charged my other camera


It's getting late where I am, and I am packing for a weekend trip, so I'll be gone till Monday. I'll check in on this thread every now and then over the weekend, and if you need any more info I'll provide as much as I can.

Dennis

 

Here is a good writeup on the Qjet and some things to look for. Pay special attention to the secondary air-blade adjustment.

http://www.route66hotrodhigh.com/PowerTuneQjet.html

There was also a really good write up on tuning a Qjet for performance, but with the website changes, I can't find it anymore.

 

How is your mechanical fuel pump? Is it new? Original to car? Oh yea, make sure all your vacuum hoses are in good condition and not unplugged, cracked or cut. Start there.

 

First thought is weak booster shot. Verify that fuel is squirting into both bores when the throttle is opened (engine off).

 

How long since it's been opened? Plugs, wires, cap and rotor replaced?

 

Hard to tell from the video but it looks like you're getting NO accelerator pump shot at all, or a very weak one. Most common cause- the accelerator pump piston cup has become hard as a hockey puck and just isn't sealing against the piston bore inside the carb any more.

 

Dist is brand new MSD as of last summer, with new plugs and coil and wires. Same with mechanical and electric fuel pump. Brand new. Had the carb open last summer as well, with mostly all new internals. Adjusted it to spec as per the literature. Went over most, if not all of the vacuum hoses as well.

First thing I'll check is the accelerator pump booster shot. When watching the video again with that in mind it does seem like nothing is shooting down the bore.

 

Is the distributor a computer control type, or the "normal" vacuum/mechanical advance type?

 

Computer control type dist. Tried it with timing set at both 0* and 6*. No difference.