Author Topic: Getting ready for first Q-jet rebuild  (Read 2007 times)

Offline wmyoung44

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Getting ready for first Q-jet rebuild
« on: April 20, 2014, 07:45:05 PM »
Hi every one.  I am new to this forum and have a new to me 1967 GTO.  Guess what??  Yep the Carb is acting up.  I have in my possession Cliffs book and a standard rebuild kit from him.  I will explain what the problems are, the specs on car and carb and then my questions.
     The car boggs down bad when you get on the gas.  If you feather it slowly it will accelerate but slowly.  Starting.  If it sits longer than 24 hours it will not start.  Putting gas directly in the primaries it fires right up and will run till that gas is gone but keeps going after the second prime.  It idles a little slow and stalls but idles OK when warmed up.  That is as much as I have noticed so far.  It had a complete rebuild by an outfit in California about 2  years ago.  I call the and they were no help stating " we only warrenty to the original owner, and I am busy got to go".

    1967 GTO  YS 400CID stock engine.  10.75-1 compression.  Carb 7027262 4MV.  intake 9786286.   Heads 670.

    I am getting ready to tear it down.
1] What can I check now on the car and off the car before I tear it down?
2]  What are the main things I should be looking for considering my symptons?
3]  Which of Cliffs idle systems should I consider or is there a better one for a stock engine?
4[   Any suggestions for a first time rebuilder and or any must does and don'ts?
5]  Any mods I should consider while I am in there?

     Thanks in advance for any help.   Bill

Offline omaha

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Re: Getting ready for first Q-jet rebuild
« Reply #1 on: April 20, 2014, 09:02:14 PM »
Congrats on having a 67 GTO, I had one of those way back when (1980's). It sounds like it is pretty muck stock I am assuming. You have a lot of the typical symptoms caused in part by the fuel with alchohol these days. I would say that a rebuild would be in order. You will need a complete kit from Cliff but I would think that not too many mods will be needed if the car is stock. Sounds like the stock carb too. The most important pieces would be the new alcohol resistant accelerator pump and the needle and seat. From there I would check to see if the well plugs are leaking as the old carbs tend to leak. Check to see if the pull-off is functioning (vacuum pump handheld or just disco the vacuum line to it while idling). As far as mods, I guess it wouldn't hurt to open up the holes under the idle screws a bit and maybe one size up on the jet. Of course, check to see if the choke is functioning for warm-up purposes.  I guess you should make sure that all the parts are of the same specs to the original cause it sounds like I wouldn't trust the previous rebuild and who knows what else has been done on the inside. OK, time to get to work

Offline omaha

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Re: Getting ready for first Q-jet rebuild
« Reply #2 on: April 20, 2014, 09:04:09 PM »
 Oh, forgot to add, check for slop in the primary throttle shaft. OK have fun!

Offline wmyoung44

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Re: Getting ready for first Q-jet rebuild
« Reply #3 on: April 21, 2014, 05:46:35 AM »
Thanks for the advice Omaha, I am hoping the last carb shop was good enough to do the throttle shaft if it was needed when they had it in, if not it will be one of the first things I will do.  I will have to study up in Cliffs book to check the choke stuff you mentioned.  I was going to do a vacuum check while on the car at the fuel inlet and see what happens before I remove it.  Any thing else I can check before removing or disassembling?