JimLentz

Is that with the engine running? If so that looks right as the choke pull off is supposed to do that. If that is with it running what does it look like before you start it after stepping on the accelerator pedal once?

lars

Mike -
You're absolutely correct, and it's the reason that I've been testing the heck out of this carb. Once in a while, I see carbs with intermittent flooding problems caused by float arms rubbing on the power piston tower, or a slightly swollen float that gets intermittently jammed in the bottom of the bowl. But on Alan's carb, I was unable to duplicate the flooding problem, in spite of finding other issues. It's possible that there was a piece of crap in the needle/seat that came dislodged during shipment. The incorrectly-installed needle clip could also have caused intermittent float control problems, but this appears to have been done when someone re-assembled the carb after attempting to fix the issue. So you're right: I have no "smoking gun" or prime suspect for the flooding issue that has been frustrating Alan. All I can hope is that the disassembly, float/needle/set replacement, re-assembly, setup, and running almost 2 gallons of gas through it during 3 days of testing has chased the gremlins out of it. The carb ran flawlessly on the test engine, and all the numbers are right on the money. The carb is now in a box on its way back to Alan, and will hopefully not become possessed again on the journey back to Alan's Vette...

Lars

AWilson

Hi guys, back home now with internet access.
To answer your question this picture was take with the engine cold. Cold as in not started in weeks! I figured I would snap the picture just before taking the carb off and sending it to Lars.
i guess we will see how it goes. I appreciate Lars doing all he can. I will let you know. It will be a while though as I am changing out heads and intake manifold.

Lars,
One thing I still do not understand. I could be wrong but you say the choke on this particular carb upon engine shut down and loss of vacuum will snap shut. And not to touch the gas pedal during restart or the choke will snap shut and flood the engine. So, how can it snap shut if it is already snapped shut when it loses vacuum on shutdown? I do not understand. It is important that I get it so I can make sure things are working as predicted and I can troubleshoot later if need be.

Either way I am encouraged with all Lars has done and can't wait to see how it goes! If I got upset about the hundreds of setbacks and unforeseen problems with this soon to be compete resto-mod I would have never completed it. Gotta roll with it and never give up!
Please advise.

lars

The 73/74 Q-Jets have a spring wrapped around the choke pulloff arm. When the arm is extended (no engine vacuum - engine OFF), this spring will exert pressure on the choke linkage to close the choke, unless your divorced choke coil/spring is strong enough to offset it. As long as you don't crack the throttle open, the choke cannot fully close, because your fast idle screw prevents the fast idle cam from rotating. As soon as you crack the throttle open, the linkage is free to move, and the choke will move to the closed position along with the fast idle cam being raised. The moment the engine re-fires, engine vacuum will retract the pulloff, and the choke will open fully almost immediately if the engine is hot and the divorced choke system is operating correctly.

You can observe this easily on the carb once you receive it: In the as-received condition, with the carb off the engine, you will note that the choke is snapped fully closed. Take your finger and push the fast idle cam fully downwards: You'll feel the fast idle screw "snapping" down the detents of the fast idle cam as you do this. Once the lever is fully depressed, the choke will be about 3/4 open, and it will stay that way until you move the throttle lever. When you crack the throttle open, the choke will instantly snap fully closed again.

Lars

lars

Here are some photos to help you see it:

This is the “typical” Q-Jet carb: It’s a 1969 with the stock divorced choke system on it. It’s the way most people think of Q-Jet carbs, and it’s simple and obvious. Notice that the choke is fully open in this static position: The plastic orange fast idle cam/counterweight is dropped fully down into the “slow idle” position, and the only thing that can raise the cam and close the choke is the divorced choke rod pulling downwards on the back side of the actuation lever. If the engine is hot and the rod is not pulling down, the choke simply stays open under all conditions, just as you see it here:


Here is the 1974 Q-Jet. The choke system is completely different. Note that the choke is fully closed, even in the static position on the workbench, and the silver fast idle cam is fully raised:


This is caused by the choke pulloff: Notice the spring wound around the lever, and this spring is pushing against the choke actuation rod, rotating it counter-clockwise against the upwards force of the divorced choke rod (not installed in this photo), closing the choke. When the engine starts and the pulloff retracts, the spring pressure is backed off, and the choke is fully controlled by the divorced choke rod position:


This is how it's easy to tell that you have a divorced choke linkage problem on your engine: Your photo shows the choke partially open with the engine not running. If the choke stays in this position even after cracking the throttle open, your divorced choke is not functioning correctly: it should allow the choke to snap fully closed, whether the engine is hot or cold. Your choke position would be normal if the engine has been shut down hot, and if the throttle has not been touched. But if the throttle is touched, the choke should snap fully closed.

Lars

doorgunner

Quietly watching and learning!

Lars.....you are a wonderful human being for taking the time to explain "all-that"!

lars

Actually, I'm an impatient jerk, but I made a New Year's Resolution to be a jerk 50% less this year than last year. My other resolution is to smoke cigars less often in the car while the grandkids are with me - at least until they're old enough to walk.

Lars

AWilson

Now I get it!! Thanks Lars! I will make sure you know how things go!

AWilson

Got the carb back, thanks. I'll let you know what happens.

doorgunner

Annnnnnnnnd..........pleeze.........take pics of each step so any problems can be corrected when Lars reviews the installation (and I can learn something LOL).

AWilson

will do.

AWilson

Ok the weather is nice so I am in the garage. Carb is back on. I HAVE NOT TOUCHED IT SINCE GETTING IT FROM LARS. I HAVE NOT AND WILL NOT ADJUST THE MIXTURE SCREWS.
The only thing I have changed is I am now using the 3 baseplate gaskets Lars suggests in order to insulate from the smiley face intake.
Results? absolutely no change at all. I am going to finish setting the timing tonight per Lars info. Then I will take videos and post. I am so sick of these troubles.
One happy note, I installed my distributor per LARS paper. That was great. It is in the correct orientation to the tach drive. I made sure I was on #1 compression stroke, set it to 8 degrees, lined up the rotor to #1 wire, used my ohm meter to get it just right. She fired right up! Then set the dwell to 30/31(it fluctuates).
So, I can follow instructions and understand most things. Please help me figure this trouble out. I want to enjoy the car this year. It is 99% done.

Cool Rocking Daddy

This carb has been to Lars twice now. He was kind enough to correct all the things that he saw wrong with it. We know it is NOT the carb.

Two things have been mentioned but not addressed by the OP. What fuel pump is on this engine? If it is anything but a stock fuel pump, more than likely you need a regulator to dial the the fuel pressure to 4.5 psi where a Q Jet likes it. So again, what fuel pump is on this car?

Secondly, you have a divorced choke. Does it have the correct rod and linkage? Is the spring in the "stove" good? Has the OP tried to adjust it to factory specs?

Engine not cranking after driving? Old wirng, bad ignition switch (common on 60's cars). Headers? If so switch to new GM style mini starter found on 1990's-2000's Tahoes and Silverados. 20 lbs lighter, rare earth magnets, gear drive. No heat soak problems with those. Others are correct, no crank after running is not a carb issue.

AWilson

Headers, yes

The fuel pump is a new replacement one. That is all I know. It is not a performance one or anything like that. I have never heard of a fuel pump regulator. My lines are all steel from pump to carb.

The rod and linkage on the divorce choke I believe are correct. The spring is new. I have not tried to adjust it. I didn't know you can or should.

engine cranking issue. ALL wires are new and not skimpy ones. So is the starter. New ignition switch. I know that no crank after running is not a carb issue. It is a different issue. BUT cranking and not starting within say 5 minutes of shut down is not a starter issue. It does that too until the battery runs down or it finally starts after I push the pedal to the floor to clear the gas.
One thing is for sure. it cranks strong when everything is cold.

im going to post pictures of the carb in all states
cold
running
shut down
shut down in 3, 5, 10 minutes. By then i believe the choke closes.
I will also try to get a video of the car running because I have long suspected that the secondaries never open. This car will not run over 80 mph and it is believved to be tuned correctly.

Example, today. I'm setting the timing per LARS. I set the dwell, pulled the advance and advance springs and set the timing. Car was running say 20 minutes. Voltage at the battery is over 14. I shut it down , put the springs back on and go to start it and it barely turns over. So now I have to wait till much later or tomorrow to start it as I need to charge it. I guess I need a different starter. But why would these starters work in 68and years later but not now?

cardo0

I can read u are fast becoming a qjet expert Al. As for the choke linkage u need to bend it for adj and sometimes heat from a torch is required but remember its a fire hazard and your vette is fiberglass that will burn also. But are u watching for proper operation? Does the choke close when cold and fully open when hot? And u can try to disable the choke by just removing the coil/dog house and taping the choke open. Car will still start but after a couple of good pumps shots in cool weather. If u dont have Cliff Ruggles book u should buy one with your all problems. Also u need to measure your fuel press as sometimes a unkown pump can be higher pressure. I use 6-7 psi on my qjet and it seems good with that. But some aftermarket pumps have much more than that which forces fuel to overfill the bowl. And i dont like fuel press regulators w/o a return down stream either. They dont work well when deadheaded at idle. From what ive learned over the years is the mech pumps self regulate very well - they have an internal bypass that works at a designed press only.

U can buy a cheap batt tester/load tester ($10) and once u are familiar with them u will want one in every car because u can test the electrical sys in seconds rather than minutes. U can test batt condition with ign off with load test. Then batt voltage by a flip of the switch. Then u can measure alternator voltage with car running. Yes a Hobo Fake unit gets it done (as much as i hate all their calibrated gear).
Its just ive never seen a starter motor become intermittent - not that it cant. It reads more like a weak batt to me. How old is the batt. Has it gone totally discharged at least once?

Last i dont know why u are pulling the dist springs. There shouldnt be a need to do so just to set initial adv. And u have to have them in to make an ign curve with higher RPM.

Ok enough for now.

AWilson

Thanks Cardo
The choke is closed when cold and open when hot.
I have replaced many mechanical fuel pumps over the last 30 years and never had a problem. But I hear I can get a loaner pressure tester from Pep Boys so I will check that out. I don't have a return

Battery: I had this problem from day one, like 3 years ago. I bought a new battery and no change, same trouble. But maybe this one is ruined now. It has been quite abused with all the problems.
I have measured voltage at the battery when the car is running. It is always about 14.3. Is it possible that it is overcharging? Maybe I should be checking my V-regulator,,,somewhow.


I am uploading a video to You Tube. It should show all the problems. and it has an exciting ending.

I followed LARS instructions for setting the timing. That is why I did it that way.

AWilson

Here is a video. At the end I tried to start it and something broke. I guess the starter. let me know what you think. If it is the starter can anyone recommend one, a specific one even better!
So I am out of commission for a while. I will return.

AWilson

Ok, the starter broke. As in busted! The aluminum casting, the bullet nose, that goes around the gears is cracked! I never heard or seen that before. Anyone else experience this? Is this a symptom or the problem all along, as in some sort of misalignment?
Need a recommendation on a good replacement.

Im thinking I have the timing messed up and always did. The video and the broken nose on the starter are the clues. If it is too advnced I am getting kickback. Maybe the marks on the timing chain cover are wrong. I'm thinking I need to do the piston stop thing to make sure of where I am at and then get a new starter. Might as well buy a high torque one. I am also going to ad a second ground to the engine. Comments on the above and again a starter recommendation would be appreciated.

Update: Thinking about a Powermaster 9500

'75

The choke should stay open as long as the engine is warn, only snaps shut when the engine is cold and you open the throttle slightly.

lars

If you pay postage costs, I'll send you one of the loaner carbs to try out. E-mail me to make arrangements if interested.
Lars