Lars was kind enough to help dignose a problem w/my Q-jet...has anyone

replaced their accelerator pump ??? A simple job or a can-o-worms ???

:confused:

 

Hey trouble -
No problem replacing the pump, but you need to pop the top off your Q-Jet. The only tricks to doing this are getting the choke rod re-engaged and making sure your power piston and primary mertering rods get properly engaged. Here is a step-by-step procedure for popping the top:

To pop the top off a Q-Jet, proceed as follows:

1. Remove the air cleaner stud.
2. Using a hammer and a small pin punch or a small finish nail, tap the roll pin holding the accelerator pump lever to the top of the carb in towards the choke horn wall. Don't tap the roll pin all the way up against the wall - leave just a slight gap so you can later get a screwdriver blade in behind it to pry it back again. Remove the accel pump lever.
3. Remove the single screw holding the secondary rod hanger to the top of the carb and remove the hanger with the secondary rods.
4. If you have a later-model Q-Jet with a choke vacuum break diaphragm that is attached to the passsenger side of the carb with two screws up high, remove the two screws and remove the vacuum break and its connecting rod. If your vacuum break is pressed into a bracket that is not attached with 2 screws up high, leave it alone.
5. Remove the choke connecting rod. There are 2 types: One type has a clip holding it to the choke lever. Remove the clip, disengage the rod from the upper lever, then twist/rotate the rod to disengage it from the lower lever inside the carb. Later model carbs have a single screw holding the upper lever to the choke shaft. On this type, remove the screw, remove the lever, and remove the choke rod by twisting/rotating it to release it from the lower lever inside the carb.
6. Remove the (2) 1/2" head bolts at the front of the carb.
7. Remove the 9 top attach screws: Two long screws in the very back; a screw on either side of the secondary airvalves; two screws just forward of the secondary airvalves; two screws just inside the choke air horn right at each primary discharge nozzle, and a single screw center front. If the carb has the stock screws in it, the two screws inside the air horn are designed to be too big to drop down into the intake manifold. But many aftermerket screws can, in fact, drop through the carb and go into the intake. Once you have loosned these two screws, use a pair of needle nosed pliers to carefully lift them out and make sure they don't drop.
8. Lift the top of the carb straight up until it clears the accelerator pump and until the air bleed tubes clear the gasket. If you have a non-removable vacuum break diaphragm, fowl the top over to the side to disengage the secondary airvalve rod.
9. Remove the gasket by carefully freeing it from the power piston/primary metering rod hanger.
10. Remove the accelerator pump.

(If this is all you're doing, stop here. If you're wanting to check jet sizes, etc., proceed to next step. Either way, if your power piston popped up and disengaged from the jets when you popped the top off, you need to make sure you re-engage the primary metering rods into te main jets ad get the power piston seated again).

11. Remove the power piston/primary metering rod hanger by pushing it down against its spring pressure and "flicking" it off your fingernail so it pops up. A couple of flicks will disengage the locking collar from the casting, and the assembly can be removed.
12. Remove the phenolic float bowl filler.
13. Remove the float and needle as an assembly.
14. Remove the main jets.

The rods and the jets are stamped with their sizes.

Only trick for re-assembly:

1. When installing the power piston, take care to fish around until the rods drop down into the jets and the power piston works smoothly. Gently push the piston nylon locking collar back into the carb casting. I've seen people not get the rods into the jets, and simply smash the top of the carb down onto the piston/rod assembly. Obviously, this will bend the rods.

Once you have the top back on, installing the choke linkage rod is considered the only "tricky" part. There is a short lever arm down inside the carb, and this arm has a hole in its end. This arm is very easy to see when you have the top off the carb, so I recommend that novices take a look at it and its orientation/function while they have the top off the carb. With the top off, take the choke rod and practice installing/engaging it in this lower lever until you get the knack of rotating the rod slightly to engage it in the hole in the lever.

Once you have the top back on (taking care not to overtighten screws and bolts), activate the choke linkage on the outside of the carb to move this lever arm to its furthest "up" position. You can just barely see it if you look down the carb. Now, insert the choke rod down into the carb, with the rod rotated slightly. Engage the hole in the lever arm at this angle, and once you've hooked the arm, rotate the rod to fully engage it.

Install the accelerator pump lever to the top of the carb. Insert a finish nail or a small pin punch through the roll pin hole to assure that it's aligned, and then use a small screwdriver to pry the roll pin back through the lever.

Install the secondary metering rods with the hanger.

NOTE: If you're going to be doing several jet changes, you do not need to attach the choke linkage rod to run the car. Leave the rod off until you're complete.



[Modified by lars, 9:15 AM 11/7/2002]

 

Shouldn't be hard at all. You need to pull the air horn (top of carb). There are 9 screws and two are hidden down in the choke area. A couple linkage rods will probably have to be unattached. If you're lucky the gasket will not get ripped but if it does you need a new one. Once the airhorn is off the accelerator pump is right there at the drivers side front (plunger with a spring on it. Just unclip it and put the new one in. Then reassemble.

Edit: I see Lars has a much more detailed approa ch for ya!


[Modified by lbell101, 10:16 AM 11/7/2002]

 

Thanks for the step by step, Lars. I'm not real comfortable dissassembling
my carb...sounds like something I'm gonna farm out to my mechanic.

 

Trust me.... if I can do it, anybody can! :lol: MJ

oh... and by the way... I dont know how many mechanics have taken the top off of a Qjet. Unless he is a rare bird he is more likely to screw it up than you are following Lars' step by step instructions.


[Modified by MNJack, 11:35 AM 11/7/2002]

 

Thanks for the encouragement...initially I was overwhelmed by Lars' lengthy text, but looking at it more closely,it might be within my capabilities.

:yesnod:

 

It's not bad at all - my steps are pretty detailed. But if you want to farm out the work, a mechanic is going to charge you a bit to do this, and the work may not be done very well. So if you don't want to do the work yourself, send the carb out to me and I'll do it for free and do it right. It will cost you about $15 shipping each way, and that's less than a mechanic will charge to do it wrong. Tag me back if you need info on this.

 

I used Lars' instructions too. It was a very easy job. Took all of 20 minutes. I even was able to hook up the choke rod on the first try.

 

Thanks for the generous offer Lars...I'll let you know if i need help
when I tackle the job.

:seeya

 

I found it rather easy contrary to what most people told me. I did how ever make the mistake of turning and fiddling a little too much. After the first rebuild the acceleration pump worked fine but it wouldnt idle right. Took it apart a few more times and it runs great.

 

Trouble -
If you post up your carb number, I can give you the correct part number (NAPA) for the right accel pump. There are two different types of pumps on the market: a regular pump, and an alchohol-compatible pump. You want to make sure to get the latter type due to the additives in modern fuels. Use of a standard pump will result in the pump swelling and seizing in the bore, and you're right back to the same problem you originally had. Also, if you drop me an e-mail, I'll send you my home ph# in case you need any assistance with the swap.

 

Jeez lars, not only are you wise in the ways of motors but you're nice too :D