Hi,I'm new to this board. I'm doing a carb for a guy's 69 Skylark that has a 350,auto. It has a 600 Holley on it at present. It has new pts,cond,rotor,cap and wires and is running pretty well. Most of its problems were fixed by the ignition parts. Anyhow I put a Borg Warner kit into the QJ---carb # is 7029244--it is the right # for this car. I also put a new Walker float in and set it to 5/16" which is what it calls for. The pump setting calls for 13/32". It's at 10/32" now;I'll correct it to 13/32". This is pump height setting(not travel)at 0% throttle. Here's what I'm wondering about: With the pump rod connected and the throttle at full travel,the primaries don't go to full vertical and the secondaries open about half way. With the pump rod disconnected,the throttle plates open all the way. I'm expecting full P&S plate opening with the a-pump connected. Is this what should happen or not? I've read that most of what happens inside is vacuum operated--assuming all the internal mechanical is functioning and set to the right specs. All the internal stuff has been cleaned and blown-out,the metering rods are undamaged and move OK,a new needle and seat is installed. Any help is appreciated.
By all rights, the accel pump should NOT affect the throttle travel. First, make sure that there is no binding in the linkage, then check the pump itself. It is possible that it is incorrect for the app. of that ot is incorrectly assembles. Typically, the pump must have the "skirt" replaced, rather than having the entire pump replaced. Be sure that it is correctly assembled. Try pushing the accel pump rod further down when the throttle linkage is at the max point. If the pump can be further pushed down , it is not the issue. Look carefully at the linkage for the binding, or obstruction. Careful inspection will likely locate the culprit. On a related note, be sure that the choke is held all the way open, as it may affect the throttle opening due to its effect on the secondaries. The choke controls the secondary throttle, not the air valves. Ray
Thanks RA. It does the same with old and new pumps...I ordered a new pump just to see if it was the same...it was. I made sure none of the linkages were interfering...choke,sec l/o,etc. The pump does NOT travel further if you push on the top of the plunger after full travel. I took it apart again to check the pump bore and noticed some pitting...I should've seen that earlier. Also,the primary metering rod spring that holds them to the hanger looks wrong...like it's homemade. They DO move up and down in the jets though. I might try another carb/core from a salvage yard about 20 miles from here.
Something to be careful of is the choke linkage. When the engine is cold, the choke linkage lock out the secondary throttles, to protect the engine. If the choke is on, or there is an issue with assembly, it will affect the operation of the secondaries. We need, at this point, to be sure of the basics before continuing. Let me know...
None of the choke or sec lockout is doing it(I made sure they were out of the way). With the pump rod disconnected,I get full throttle travel and opening of P and S plates. That's what makes it seem confined to pump rod,lever.pump itself or pump return spring. The bore has some pitting but the pump moves up and down and you can hear the effect... a sound of air being pushed. I made a shorter pump rod out of solid copper 12 ga wire and got full throttle. The side effect was that it made the pump height too high...sticking up through the air horn too far.
If the pump rod now performs correctly, it may be a benefit, as the extra pump shot may alleviate any hesitations. If everything is now correct, good luck.
I might look into a shorter pump and/or pump return spring(if such things exist). Thanks for the input;it is appreciated.
I think there are issues with your accel. pump assembly. The pump shaft should still compress even after full pump-cup travel as the assembly is spring loaded and compresable. A shorter pump shaft can give you more pump volume. If you cant find a better pump, give me a call or check out my website for Q-jet parts. Also, make sure you have a good quality Viton pump cup that can stand up to todays pump-gas fuel with alcohol.
A shorter pump or shorter return spring (if there is such a thing)...I'll look at your site... I think my pump is 2 5/8" and the return spring is 2 1/16" but I'm not 100% sure at this time. I'm at work and the carb is at home. Nice cars and web site!
