carb floods easily!
05-09-2015, 11:38 AM
#61
Drifting
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Yes, I realized that later last night. thanks! Or are you saying that it should not be slowly closing almost immediately after shutdown? I will time how long it takes to fully close. Even take time phased pictures.
Last edited by AWilson; 05-09-2015 at 11:50 AM.
05-09-2015, 11:44 AM
#62
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Let me get everything else organized again and we will see. I have to get the poor starting issued solved first so I can concentrate on my other problem. I have to cross off possibilities as I go along so that I do not go around in circles.
I'm buying a starter, going to use a piston stop to make sure I know where TDC is, then reset the timing.
It is probably not a big problem. I just don't know enough.
I took out and labeled all the plugs. I will try to post good pictures. To me most are black and sooty and or sticky. Like they have been running rich I believe. I will put in new plugs too but I estimate these only have a few hundred miles on them.
I appreciate your help Lars
Last edited by AWilson; 05-09-2015 at 11:49 AM.
05-09-2015, 12:53 PM
#63
Starter broke because it is probably missing the brace that bolts to the back of the starter and to the engine block.
You've already gotten a recommendation for a starter. Remanufactured GM starter from Advanced Auto, O'Reillys, Pep Boys. 2000 and up Silveradoe, Suburbans, and Tahoes. $125 with lifetime warranty. As said, rare earth magnets, gear reduction, 20 lbs lighter.
You've already gotten a recommendation for a starter. Remanufactured GM starter from Advanced Auto, O'Reillys, Pep Boys. 2000 and up Silveradoe, Suburbans, and Tahoes. $125 with lifetime warranty. As said, rare earth magnets, gear reduction, 20 lbs lighter.
05-09-2015, 04:24 PM
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05-09-2015, 06:30 PM
#66
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Starter broke because it is probably missing the brace that bolts to the back of the starter and to the engine block.
You've already gotten a recommendation for a starter. Remanufactured GM starter from Advanced Auto, O'Reillys, Pep Boys. 2000 and up Silveradoe, Suburbans, and Tahoes. $125 with lifetime warranty. As said, rare earth magnets, gear reduction, 20 lbs lighter.
You've already gotten a recommendation for a starter. Remanufactured GM starter from Advanced Auto, O'Reillys, Pep Boys. 2000 and up Silveradoe, Suburbans, and Tahoes. $125 with lifetime warranty. As said, rare earth magnets, gear reduction, 20 lbs lighter.
05-09-2015, 06:47 PM
#67
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Most times when I go to start the car aftr it is running it will not start. But it is complicated by a general lack of ability to turn over as witnessed by the video.
Let me solve the cranking problem then I will get back to you.
Here is my plan:
Buying a new starter
I already checked that my TDC mark is truly TDC, (it is).
I have changed my plugs. They look bad, some sooty and I believe gummy.
I will make sure I have a good battery. and good wires/connections
Then I will start the car and set the timing.
After I have the weak cranking problem solved I will start over assessing if the car is hard starting.
I will let you know. Probably some time late next week.
05-26-2015, 11:00 AM
#68
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OK, I bought a replacement starter and installed it. A little early to be 100% sure that things are fixed but here is what I learned.
The starter was binding causing an increase in power requirements.
The positive lead was tight on the battery but the wire was not tight on the battery terminal. The ground wire from the engine to the block was loose.
All these things were fixed. Now the car cranks fast. It starts up well and again too early to tell but I believe my supposed carb problems are gone. I will have to drive it a while to be sure.
I guess the very slow cranking rpm fooled me to think the car was flooding because it took forever to clear any error in throttle movement when starting. The car now starts all the time. I will post an update once I gain more trust in things.
Bottom line, is to solve your problems one at a time so you know where your at. Otherwise it is too complicated as there are too many variables.
Thanks and apologies to LARS. It doesn't seem to have been a carb issue at all.
The starter was binding causing an increase in power requirements.
The positive lead was tight on the battery but the wire was not tight on the battery terminal. The ground wire from the engine to the block was loose.
All these things were fixed. Now the car cranks fast. It starts up well and again too early to tell but I believe my supposed carb problems are gone. I will have to drive it a while to be sure.
I guess the very slow cranking rpm fooled me to think the car was flooding because it took forever to clear any error in throttle movement when starting. The car now starts all the time. I will post an update once I gain more trust in things.
Bottom line, is to solve your problems one at a time so you know where your at. Otherwise it is too complicated as there are too many variables.
Thanks and apologies to LARS. It doesn't seem to have been a carb issue at all.
12-18-2016, 08:13 AM
#69
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Ok a year and a half later and I am responding again. Working on different issues off and on during this period. A couple of months ago I finally have the carb doing all it can do.
There were many issues that had me going in circles. Mostly because I didn't know what I was doing and became easily confused. Between starter, battery and carb problems I was frustrated. But the biggest issue was I had no idea what I was looking for. I had no idea what or how this car should perform.
Now I do!
I am embarrassed to say it but I figure It needs to come out because I wouldn't want anyone to go through this as long as I did!!
My accelerator pedal was not moving the carb arm full motion. As in about 2 inches short of full travel! The secondaries were never opening!
I fixed all that and now the car is fantastic! I have huge bucks in this engine and I was grumbling and griping thinking that this is the best 68 technology can give me. I had no reference point. Driving without secondaries. Disgusting!
When I worked through my engine build here on the forum, years ago, I was pretty assured I was going to have a fun street machine. But everyone's perspective of that is different. I never trusted myself.
So all is good now. The car frightened me for a couple days till I got used to it!
383, camel hump heads, Muncie close ratio, 3.70 rear pumpkin, headers, cam for low end torque for street play.
So I had about a month of terrorizing the neighborhood like a dumb kid.
All is good. (except for the snow and -15 coming tonight) Can't wait till March or April!
So Lars was correct on all points with only one exception, that being the carb was messed with. It NEVER was after his initial rebuild, or since. But regardless I appreciate all his extended efforts. Thanks LARS and all contributors.
I need to get some detailed pictures of my beautiful car and info on the build posted over the winter.
There were many issues that had me going in circles. Mostly because I didn't know what I was doing and became easily confused. Between starter, battery and carb problems I was frustrated. But the biggest issue was I had no idea what I was looking for. I had no idea what or how this car should perform.
Now I do!
I am embarrassed to say it but I figure It needs to come out because I wouldn't want anyone to go through this as long as I did!!
My accelerator pedal was not moving the carb arm full motion. As in about 2 inches short of full travel! The secondaries were never opening!
I fixed all that and now the car is fantastic! I have huge bucks in this engine and I was grumbling and griping thinking that this is the best 68 technology can give me. I had no reference point. Driving without secondaries. Disgusting!
When I worked through my engine build here on the forum, years ago, I was pretty assured I was going to have a fun street machine. But everyone's perspective of that is different. I never trusted myself.
So all is good now. The car frightened me for a couple days till I got used to it!
383, camel hump heads, Muncie close ratio, 3.70 rear pumpkin, headers, cam for low end torque for street play.
So I had about a month of terrorizing the neighborhood like a dumb kid.
All is good. (except for the snow and -15 coming tonight) Can't wait till March or April!
So Lars was correct on all points with only one exception, that being the carb was messed with. It NEVER was after his initial rebuild, or since. But regardless I appreciate all his extended efforts. Thanks LARS and all contributors.
I need to get some detailed pictures of my beautiful car and info on the build posted over the winter.
Last edited by AWilson; 12-18-2016 at 08:14 AM.
12-18-2016, 10:20 PM
#70
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Well congratulations and sharing your experience here will be a huge benefit to those trying the same improvements. I guess its the passion for performance that drives us all here just by owning a corvette. But there is always new and unique problems which can become overwhelming. I guess we all have to start somewhere and time can be a consideration to as we only live once and most everyone has more than just a corvette on their bucket list. My favorite advice is to spend more time learning to tune the car mastering the carb and timing curves before taking the engine apart to prevent surprises when the motor is reassembled. Well i do hope you hang around enough to prevent someone dream build from becoming a horror story.
Thx for posting all that experience.
And congrats on getting your dream build going like you wanted.
Thx for posting all that experience.
And congrats on getting your dream build going like you wanted.
Last edited by cardo0; 12-18-2016 at 10:22 PM. Reason: to/you
03-10-2021, 09:05 AM
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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
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
Sorry to dig up this thread but I have been searching all over about the QuadraJet's choke pulloff its spring where a divorced choke is used. I have a 1972 C10 with a 350 / TH350. The previous owner installed a Quadrajet 17058213 (78 GMC Truck) that he got from a auto parts store (replacement). I believe I should have a 7042208, which I have sourced and is out for rebuild but won't be ready until May 2021 (if I am lucky). Again, I do have a divorced choke.
The Quadrajet 17058213 is running good and cold starting I haven't any problems, the Choke closes and fast idles just fine. When we had our Texas Winter Storm (dropped to 7 degrees here) she started like a charm!
My problem is after reaching operating temperature, say after driving around 10 miles or so, then I shut off, I have a hard start after roughly 5min ~ hour later. I turn her over for ~5 seconds and she doesn't run. I stop, give her a bit of gas by lightly touching the peddle and turn her over. She starts then and perhaps she struggles a little for a few moments. Though often I just rev up to about 1k or so for a few seconds to get past the struggling.
So my question is about the Warm Choke Position at Shut Off / Start up during this 5min ~ hour period. What is the Choke plate suppose to do during this warm time shut down? In my case when I shut off, the Choke mostly closes and the best that I can tell is that spring is keeping down pressure on the divorced choke, thus closing the choke plate a bit. Soon as has the engine starts up the choke pulloff gets its vacuum and the choke plate snaps fully opened.
I don't think the choke plate being part/mostly closed is the full issue with my warm starting but I am thinking the air being restricted is not helping matters. That is assuming what I am seeing with the choke plate after proper warm up / shut down is even a issue. If that is improper operation, how do I adjust that out and I guess not effect what is working (cold starting choke properly closed by the divorced choke).
03-10-2021, 11:41 AM
#73
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Hi, I do know it is generally bad etiquette (which is why I started off saying sorry) but I never actually ran into a form rule not to do it. So I do now apologize for breaking a rule - however Lars's post that I quoted was really spot on what I been looking for and I am "hoping" he is still subscribed to this thread. I thought about PM'ing him but that seemed to be rude and I am hoping my question that is expanding on the Choke might help others.
Again, apologizes for breaking a forum rule, thank you for taking the time to point that out - perhaps you can blame it on me being a Chevy Truck owner and not a vett
Richard
Again, apologizes for breaking a forum rule, thank you for taking the time to point that out - perhaps you can blame it on me being a Chevy Truck owner and not a vett
Richard
Last edited by Rich72C10; 03-10-2021 at 11:41 AM.