1973 Buick Other Repair Question
1973 Other Buick Models Acceleration
1973 Other Buick Models V8 Two Wheel Drive Automatic 175000 miles
I've recently had the carburetor (4 barrel), the distributor, points, and plugs overhauled in my 73 Buick Centurion 455. My problem is that it accelerates fine for easy increases in speed. But it won't go into passing gear. As a matter of fact, if you stomp the gas completely (and suddenly), the car will not respond- it will just cough without power. Why will it respond to easy acceleration with its usual ease, but not hard? I always keep 93 octane gas in the tank since the owner's manual calls for 91 or better. Thank you in advance.
Check the choke, sounds like its not opening fully. Or you have a bad rebuild on the carb, secondaries clogged still.
what's the easiest way to check if the secondaries are clogged? how do i check for a choke that isn't opening fully and how do i adjust it?
Check the secondary by opening the throttle all the was, the secondary part or the two large barrells in the rear shold open, and squirt some gas in. Do this with the car off of course. If they dont open, the linkage to it needs to be adjusted, do that by bending the little rods that go to the secondary. As for the choke, with the car cold before the first start, open the throttle and release, the choke should now be closed all the way, as the engine warms up, it should open all the way, it will be in the striaght up position. To adjust it, the black round bakelite thermostat cover have several screws, usually 3, loosen the screws and adjust to be closed for the first start, just enough so it closes, but not so much too force it closed hard! If it dosent adjust well or open fully, youmight need the bi-metalic spring inside the cover, this is the thermostat.
so, when i squirt a little gasoline into the secondaries, what should that accomplish? clear the clog if there is one? do i start the car after squirting gas in? also, i was under the impression that the only way to get the secondaries to open was to put the car under load (heavy acceleration or something) while moving not sitting still. does loosening and tightening of the bakelite screws adjust the choke? also, are there two sets of screws (one for cold choke and one for hot) or do you just adjust for cold and hot takes care of itself?
If you can post a picture of the carb, I will get more detailed on adjustment, It has been a while since I have SEEN a carb, let alone adjust one, last time was my 79 Tans am rochester. You don't squirt the gas, the carb should when you full throttle it, do it with the engine off. Does the secondary open?
unfortunately, i don't have a digital camera (or a camera phone). so, i uploaded pictures from the internet that are the rochester 4 bbl carb that is in this car. as for the secondaries, i'm confused. when you say 'open the throttle all the way' do you mean press the gas pedal all the way down, or just manually push open the throttle plates completely? i can manually open the secondaries and they spring shut again but won't open on their own. as for the choke, when the car is cold, it is closed just like you said it should be- not jammed, but not loose. however, after it is warm/hot, the choke plate is not completely open (90-degree angle). it's probably 80 degrees at best. is this good enough or does it need adjustment?
Choke may be good enough as long as its not closed by the vacuum created at the throttle, and yes open the throttle by hand so you can see if the secondaries are opening at full throttle, also the DETENT cable to the transmission is hooked up right?
The other adjustment for a gas starved engine is the mixture screws, basic setting is turn each one(two screws) all the way in gently, then back out 2/12 turns, then use a dwel meter and fine tune them until the highest RPM is reached. Then set you idle speed.
the secondaries do open when i open the throttle manually. i attempted balancing the carb in the event the mix was too lean. unfortunately i do not have a dwell meter. i had to do this the 'old-fashioned way'-- by ear. from the sound of the car in motion, i think i have it a little too rich but that can be fixed. i'm still having the same problem with abrupt acceleration (the cough without power). what is DETENT cable to the transmission? how do i make sure it's hooked up right? would timing cause a problem like this, but allow regular driving without problem? i know from the last time the car was in the shop, the dwell is 30, the range is 28-32 for this car.
Check fuel pump pressure and volume, 9psi or so, and 1 pint in 30 seconds, Try adjusting that choke so it's fully open when fully warm. Check for ANY vacuum leaks, the advance in the distributor may not be working...check for leaks with spray gumout, and spray vac lines and manifold, if the idle changes, you found a leak.