Northcutt Level 2 Q-Jet Issues - Resolved

Discussion in 'The Venerable Q-Jet' started by Brett Slater, May 15, 2017.

  1. Brett Slater

    Brett Slater Super Moderator Staff Member

    Not for nothing but my Q-Jet experiment is over. This is probably a nice carb but it's not for me.

    There's just too much involved and this was not fun for me. I didn't buy this car not to have fun, you know?

    So, if I send it back to you, I'm doing so in the hope that you'd be refunding my money, otherwise I'm offering it for sale here on the board and maybe someone more proficient will grab it.
    sean Buick 76 likes this.
  2. Stage 2 iron

    Stage 2 iron Well-Known Member

    Hey Brett, I no your frustrated with q-jet, but you said on your first post, that you had a hard time keeping it running when you put it on, an it was low on gas you my have sucked some trash out of the gas tank an clogged the fuel filter on the inlet did you check it? Also check the fuel lines by the fuel pump when the car is running they may be deteriorated an collapsing from the pressure from the fuel pump it happened on my car because of todays fuels replace all the hoses with fuel injection hose of the same diameter. When a Q-Jet is tuned right it will run just as good as a holley, or better an get better gas mileage the best of both worlds. Hopefully this can help.
    Last edited: May 17, 2017

    STAGE III Lost Experimental Block

    yeh if that is a brand new carb I agree with Frank on sucking up the trash off the admittedly low fuel level in the gas tank. The new q-jet carb sucks the garbage up and is removed WITH the garbage in its filter and magically the Holley does fine. I'd be checking that filter on the Q-jet as Frank suggested and I hope it then runs like a scalded dog
  4. Brett Slater

    Brett Slater Super Moderator Staff Member

  5. Stage 2 iron

    Stage 2 iron Well-Known Member

    Filler looks good just throwing out ideas.
    Brett Slater likes this.
  6. Brett Slater

    Brett Slater Super Moderator Staff Member


    I sent you a PM yesterday. Please advise.

  7. Stage 2 iron

    Stage 2 iron Well-Known Member

    Hey Brett quick question did you try putting your hand over the choke when The car is running if the RPMs go up you have a vacuum leak either in the carburetor or intake manifold Spray carburetor cleaner on the outside of the carburetor while it's running on the throttle shafts again if you RPM went up then one of the shafts is sucking air . I've been having that problem with an NOS stage one carburetor . Try putting your hand over the 850 holley to rule out the intake manifold from leaking . The car should cut off .
    Last edited: May 19, 2017
  8. Brett Slater

    Brett Slater Super Moderator Staff Member

    Tried that as well.

    No go.
  9. Stage 2 iron

    Stage 2 iron Well-Known Member

    Why don't you just send it back to Mark and see if he can get it running on one of his cars Somethings going on with it . Does your car have a cam in or is stock ?
  10. Brett Slater

    Brett Slater Super Moderator Staff Member

    Stock cam with Mickey Thompson Super Scavengers, 3" exhaust and a B4B.

    I thought about sending it back but I'm probably going in a different direction. This whole process has begun to take the fun out of buying this car.
  11. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    we all tried to help you diagnose the problem. we asked you direct questions to which you answered vaguely. did you actually check to see if the Q-jet was at WOT with the pedal to the floor? you said it "felt good" ???

    the thrill is gone already because of this?
  12. Brett Slater

    Brett Slater Super Moderator Staff Member

    I appreciate the help and feedback, so please don't think I don't. Also know that I've been out of the game for a long, LONG time and a lot of this is new to me. So, please bear with me.

    All of the suggestions were attempted - with the same results. A car that ran fine with the Holley that came with it (until it started acting up) ran like it was firing on 4 cylinders when this carb was installed. Timing was right, idle adjustments were done as suggested. The pedal was fine at WOT.

    Two very experienced mechanics took a stab at it with the same results. I might give it one more try this weekend (or next week) and the thrill isn't gone. I'm just frustrated, as I mentioned earlier.

    To me, installing a brand new carb from a reputable place, means it shouldn't take this much work to get it to run right. That's all I'm saying.
  13. TORQUED455

    TORQUED455 Well-Known Member

    I'm really having a hard timing following this. You say you swapped intakes and carbs and the "problem" started. Can you be more specific? Can you also define "lazy"? Part-throttle, WOT, hot, cold, etc? The Holley carb "messed-up" too? Which carb makes it seem like it's running on 4-cylinders? Mark has a good handle on Qjets. I think it's a little presumptuous at this point to blame his carb, and he is offering to help.
  14. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    at the same time it isn't a headlight. some adjusting is required.
  15. hugger

    hugger Well-Known Member

    Cut that filter open looking at the outside is pointless, cut it and pull it apart.
    Couple things
    1. Pull Carb top plate off and clean bowl and needle and seat
    2.idle mix 1.5 turns from closed
    3. Idle speed screw 2.5 turns once it contacts arm base gasket, stack two thin ones or one of the thicker ones
    5.adjust idle mix evenly till max vac/rpm is reached then lower idle speed screw, this only applies if timing is set where you want it.
    If it does better and you feel it's ready to drive, if it stumbles off idle increase timing till it clears , jusy make sure you don't get it to pinging, if it's got decent comp it will rattle with more than 30° more than likely.

    If it bogs going into the secondaries I usually loosen the air door, seems like 90% of the time it needs to open quicker, if bogs worse then tighten it.

    ALL carbs no matter who built them or what they were speced for are going to need adjustment. Your altitude, weather,fuel,fuel system health, barometer etc etc will cause adjustments to be made

    Check for Vac leaks around the intake,fittings etc etc.
    Mike B in SC likes this.
  16. Brett Slater

    Brett Slater Super Moderator Staff Member

    Well, it lives.

    Shoutout to Paul Massicotte - for not only taking time out of his busy life to help me rectify the problem (and showing up with enough tools and parts to build another car) but for also aiding me in utilizing the Q-Jet, which is what I had intended on in the first place.

    I know I threw in the towel a little early and I don't want any of you to think I didn't appreciate the advice, because I did. I'm back to novice stage at this point and having been out of "the game" for as long as I was, I'd essentially forgotten how to work on and fine tune a car - as well as ALL the other intricacies that accompany doing such. I got frustrated and like a child, took my toys and went home.

    Today: Paul meets me where the car is garaged and I give him the lowdown. Initial check of the timing (that I was sure was fine) was off considerably. I'll plead ignorance on that issue.

    Once the timing was squared away, it was determined that the 750 Holley - that my friend rebuilt a few years ago - was no bueno. The only thing to do was put the Northcutt Q-Jet back on and start from scratch.

    Once that was squared away and after a little tweaking, it was good to go. The test drive went without a hitch and when we got back, we made a couple more adjustments, timed it again and called it a day.

    I can't even begin to say how grateful I am that Paul not only took a few hours away from his family to help but has left an open invite should any other issues arise. He's a true MASShole and a true testament to what this board is all about. As for everyone else who probably was just as frustrated with my replies as I was with the situation, thank you!
  17. David G

    David G de-modded....

    Brett, that's awesome, glad to hear Paul was able to right the ship with the Qjet. Were there any specific carb adjustments required?
  18. Brett Slater

    Brett Slater Super Moderator Staff Member

    Just what Mark had layed out in his "directions".

    We played around with it a bit but got it right. Paul ran a vacuum test on it while adjusting it.

    My sense tells me this poor motor took a good beating at the hands of the high school kid who blew the original motor back in the very early 80's. I'm sure it could use a freshening up 36 years later and we surmised that the distributor is probably "walking", which would explain why the timing was - and still probably will be an issue.
  19. Stage 2 iron

    Stage 2 iron Well-Known Member

    Glad to hear you got your car straightened out hey don't beat yourself up too bad we've all been here my cars been sitting for the last 15 years plus raising a family and other allegations . So one of my cars need a fuel pump replaced because of sitting so I tried to replace the fuel pump and forgot you have to bring the motor to top Dead center of cylinder number one I didn't do that I tried forcing it and it broke the arm off the fuel pump an to turned into a bigger project than I wanted .
  20. Brett Slater

    Brett Slater Super Moderator Staff Member

    I'm not entirely out of the woods yet. It wouldn't start this morning - pretty sure that distributor is junk.

    As for that TDC comment, I didn't either when I installed mine last week. God help me!!

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