Very Fast Startup RPM

Discussion in 'The Venerable Q-Jet' started by MNBelv57, Apr 3, 2019.

  1. MNBelv57

    MNBelv57 Well-Known Member

    Hello all, I'm having a problem with the Q-Jet on my 75' Regal 350. The car sits a lot and I know that this is part of the problem but it has been very frustrating dealing with carburetor issues the past few years and because of this I often don't feel like driving the car. To give a background this is an 800 cfm Fred Catlin built carb. custom made for my engine. I bought it around 1992 and it sat in the box till I installed it on the engine quite a few years later. The engine is rebuilt with only a few thousand miles on it and it has the c118 Kenne, -Bell cam, T/A Stage 1 aluminum dual plane intake with 1" spacer, TH-350 trans and KB 2200 stall converter. The car runs very rich and the exhaust smells and burns your eyes. As I said the car sits a lot and the other day when I tried to start it up, the engine revved up to 2000 or more RPM's. I shut it off right away because I was afraid of that kind of speed on a cold engine. I figure it must have something to do with the choke which is the stock heat coil type with the exception of being heated by an aftermarket tube that attaches to the headers. I tried to adjust the choke screw but nothing seemed to happen and the idle speed screw isn't even contacting the throttle arm so I can't try to adjust it down. I disconnected the throttle cable and found that if I pushed the throttle arm slightly back from its seated position the idle speed did come down but only slightly. It wasn't till I started playing with the choke butterfly with my hands that the idle started to come down but then the engine was "choppy" and very rich. When the car is running properly it is a joy to drive. I just want to try what I can before I absolutely know I need a rebuild. I know I can always rely on all of your good advice so any help you can give is greatly appreciated.
    Mario.
     
  2. buick64203

    buick64203 Just plum crazy Staff Member

    I'd probably take the carburetor apart. First and foremost to put some fresh ethanol compatible gaskets and accelerator pump in it. Second, you can see what rods and jets are in it.

    Have you tried adjusting the mixture screws to lean it out? The cold idle rpm has its own screw on the right side to raise and lower it. Have you tried adjusting that?
     
  3. Stevem

    Stevem Well-Known Member

    Since the car sits a lot I would also check for dry rotted and or cracked vacuum lines.
     
  4. Cliff R

    Cliff R Well-Known Member

    If it's a 1975 Buick carb I would convert it to electric choke and get rid of the rigged heat tube down to the header. That system requires a "loop" to keep dirt out of the engine, but it's 2019 and we are WAY past using hot-air chokes for non-stock applications. Go electric and never look back.

    Also make sure that if you are running a 1" spacer on a dual plane intake that your spacer has a divider in it, not open. This can and will cause running issues, and to be perfectly honest using a 1" spacer for a street driven car in most cases is a waste of time/funds.

    I've tested all sorts of spacers and every intake that will fit under the hood of my car. The last time we did a private track rental were I could make as many runs as I wanted I tested 4 different spacers on a dual plane intake. The only one that showed any promise was a divided spacer with a little material removed between the secondaries.

    As fast as my car is it still lost a little in 60' times and picked up a little on top end, pretty much a "wash" far as ET and MPH. Certainly not worth the effort of "cobbling" things up by raising the carb up an inch vs having it sit right on the intake and everything hooks up and fits like it's supposed to.......Cliff
     
  5. MNBelv57

    MNBelv57 Well-Known Member

    No, Jason, I did not try to adjust the mixture screws yet. I wanted to get some advice before starting with anything. I did try to adjust the choke screw that is on the bottom passenger side towards the front. I will try what you suggested with the mixture screws. I will check my vacuum lines too,thanks for that Steve. Cliff, I have an electric choke on an old Holley. Do you think that would fit on a Quadrajet ? One last question to all of you. Since this carb. is custom built, will I mess anything up with the special calibrations if I try to open it up and work on it myself ? The jets in there are the street ones. Mr. Catlin also provided racing ones that I have not used yet. Thanks for all the good info guys. I will post my results and if you know any Buick owners who hang out in the New York City/ Long Island area please let me know. I haven't had time to take advantage of any cruise and show spots lately but I know they are a valuable source for tuning tips especially the Buick specific ones. Thanks again, Mario.
     
  6. BrunoD

    BrunoD Looking for Fast Eddie

    Welcome to V8 Mario,Jason there lives on Long Island and so do I.Jason lives in Suffolk,I live in Nassau.We have a big number of Buick guy's in the area.We also belong to the NorthEast GSGN club .We usually have a get together after Christmas and in the spring.Matter of fact,we will have a spring meeting this Sunday,weather good,most likely about 70 members will be there.Bruno.
     
  7. buick64203

    buick64203 Just plum crazy Staff Member

    Odd that you wouldn't adjust a new carburetor on install and set the mixture screws on it with a vacuum gauge.

    I would turn both screws in and bottom them out, noting hoe many turns of the screw it took to do it. That way you have a baseline and know where you started from. You can either turn them back out the same amount and adjust from there, or unscrew them 1.5 turns and adjust. 1.5 turns out which is good starting point on a new carb.

    Make sure you install a vacuum gauge and adjust the screws to the highest vacuum reading. That should get you in the ball park at least. Let us know what vacuum reading you get
     
  8. MNBelv57

    MNBelv57 Well-Known Member

    Thanks Bruno, if I can get the car running properly this weekend maybe I can take a ride out there and meet some of you guys. Jason, thanks for the help and advice. Please forgive what seems like complete inexperience and my not performing procedures that should seem to be second hand, although I have been wrenching around cars as a hobby for about 34 years now, my life is often hit and run when it comes to working on them and for me if I don't do something often enough I get pretty rusty. So, sometimes my questions may seem redundant or naive, but it's because I want to make sure I don't screw anything up. Thanks for everyone's patience and keep up the good work.
    Mario.
     
  9. buick64203

    buick64203 Just plum crazy Staff Member

    Your welcome to come out here one weekend and we'll wrench on it. Im sure Larry would be up to lend a hand as well. This weekend is the spring meet in Chappaqua, but the following weekend is open weather provided. Just let me know. I'd love to take a look at it. Im out by McArthur Airport off exit 59 on the LIE
     
  10. MNBelv57

    MNBelv57 Well-Known Member

    That's great Jason. I'd love that. I'll keep you all posted on how things are going. Thanks again.
     
  11. telriv

    telriv Well-Known Member

    Why not just come to the meeting???? They sometimes mess with minor things afterwards. Sounds kinda minor to me anyways.
     
  12. MNBelv57

    MNBelv57 Well-Known Member

    Where's the meeting Tom ?
     
  13. telriv

    telriv Well-Known Member

    Do a search on this forum for Northeast GS/GN spring meeting April 7th, 2019
    All the info you need is there plus directions.
    Maybe you could follow Jason or Larry up???
     
  14. Cliff R

    Cliff R Well-Known Member

  15. MNBelv57

    MNBelv57 Well-Known Member

    Hello guys, I played around with the carb. last night. I sprayed the linkages with carb. cleaner then adjusted the mixture screws. Turns out they were already about one and a half turns out. When I started the car up the idle was a little lower this time and the engine seemed to be running smoothly. I let it warm up then manually hit the throttle a few times to take the choke off. It finally did come off and the engine idle went down drastically and it started running rough and rich but now the throttle arm was in a position where I could turn in the fast idle screw to bring up the RPM's. By this time the plugs had fouled again. I cleaned up one bank and called it a night. I'll try to get out there again today and clean the rest of the plugs. I think that the choke and some of the other parts might have been just stuck from all the sitting. Thanks for the electric choke link Cliff. Tom, I won't be able to make it to the Spring meet as I have something to do with the family but if there is a cruise spot where you Buick guys hang out maybe I can meet you there once I get this car running right. I spoke to a guy a few years ago at the Pep Boys by me who had his maroon colored 67' GS with him. He mentioned that his Long Island club hangs out at Captree State Park on Sundays in good weather. I don't know if any of you heard of this or the club. I think it was called the Long Island Buick Club. Also there is a weekly show starting around this time and until around September in Oyster Bay. A lot of nice cars there and usually one or two Buicks. It is on Tuesday nights and they close off one of the main streets and usually have a live band playing oldies. Well that's all for now. I'll keep you posted on the progress.

    Thanks again, Mario.
     

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