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Discussion Starter · #1 ·
I'm saving for one of the EFI systems on the market for my Chevelle but I have a Holley 600dp on my '71 Nova. I bought this directly from Holley as a reconditioned unit. It has no choke but its very hard to get started even in the summer. I'm ready to start driving the car but it literally can take 10 minutes of foot on the gas before it will idle and accept gas. I've have a lot of Holleys in my day and even drag raced several so I know basic tuning and adjustments. I've never dealt with one like this though. The set up is below:

Stock short block 350
double hump heads
small cam of unknown size
dual plane aluminum intake with 2" carb spacer
HEI ignition
Hookers

Do you think the carb spacer is the culprit? I'm only using it because the carb hits the vacuum connections in the intake. I've got a rebuild kit coming from F.A.S.T. so I can make sure all inside is to spec. I need to also jet it down a few sizes as it runs a little rich once its warn. Any help or tips is very much appreciated!!
 

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if the accelerater pumps are working you should be able to pump the accelerator once and it should fire immediately even if theres something wrong with the idle circuit.how much voltage do you have at the hei batt term when running?
 

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Not too far south of you in SC, my 66 has an old Holley 01850 manual choke carb. I did not want to run a choke cable so I just wired it wide open. Also a 350 with 882 heads, HEI, Eddy Performer intake and a Comp XE262.

It starts hot or cold and can be driven away almost immediately. Being a stick makes it easier.

I was thinking about adding the elect choke but really don't seem to need it. If the ignition and carb are good and adjusted, it should fire and be able to drive off within less than a minute.
 

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66 El Camino 57 Chevy pickup 2004 Tahoe
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you need a choke. this was mature technology in the 40's.

That said, most dbl pmprs are so pig rich you can get by without a choke. give both idle mix screws 1/2 turn out or CCW, see if it helps.

What is the timing set at?
 
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choke would definitely help cold drivability but from the postit sounds like the biggest problem is it just doesn't start. if the accelerater pumps are working i would look at ignition. once its running it could have some carb problems as well . how does it run after its warmed up? does it idle ok? you may have a big vacuum leak. check out the basic tune up. idle mixture timing etc like tom said.
 

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Discussion Starter · #6 ·
Thanks for the replies!! Timing is set to 10 degrees BTDC. The HEI is from Summit and I'm not sure what the curve is or when its all in. It will start after a few pumps but will not stay running. Its 5 or 6 times cranking before I can keep it running with the pedal. The car seems to run fine after its warm but I have to admit, its not currently tagged and insured but I've taken it out for several night time trips through the neighborhood. I am going to replace the pump diaphragms and jet it down a few sizes when the kit comes in next week. I understand that these carbs are old technology but I know it should run better than it currently is. Thanks again for all of your help!!
 

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ok so it does start . whats the weather like where you are? if its 35 degrees or so its going to be extremely cold blooded without a choke. with the air filter off look down the carb and operate both accel pumps . make sure each has a strong shot. with the car warmed completely up check the idle mixture and float level. it should idle best with that carb less than 2 turns from seated. check with a tach or vacuum guage. 10 degrees timing is ok with the vacuum adv line removed but it would idle better with a little more timing say 15 degrees if it has a small performance cam. hook the advance to manifold vacuum if you havent allready. if you are running the hei through the original cloth braided resister wire that needs to be changed to have full voltage at the dist. the voltage drop through the wire coupled with cranking can drop the voltage enough to cause hard starting although you say it starts quickly initially. once the carb and ignition is tuned correctly it should run just about as good as a well tuned fuel injection system. for seemless cold starts and cold drivability you need a choke especially if its cold. everyone thinks fuel injection is the answer but those old mechanical systems like carbs and chokes, heat riser efe etc. work really well when they're set up right
 

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An old fashioned hand choke fixed mine.
I give the accelerator a couple of pumps, pull the choke all the way out, start it up, push the choke about half way or so back in and go.

The only problem is once in a while I forget to push the choke all the way back in. :(
The original Dashboard Camshaft......lol......
 

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You have a Holley [ for once ] that is actually doing what it should do: requires a choke until it warms up.

If started & ran without choke, expect it to run pig rich once warmed up.....
 

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66 El Camino 57 Chevy pickup 2004 Tahoe
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move the timing up 6 or 8 degrees, see if it helps.

If you get burned out on it, send it to me, I'll fix it and send back.
 

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Thanks for the replies!! Timing is set to 10 degrees BTDC. The HEI is from Summit and I'm not sure what the curve is or when its all in. It will start after a few pumps but will not stay running. Its 5 or 6 times cranking before I can keep it running with the pedal. The car seems to run fine after its warm but I have to admit, its not currently tagged and insured but I've taken it out for several night time trips through the neighborhood. I am going to replace the pump diaphragms and jet it down a few sizes when the kit comes in next week. I understand that these carbs are old technology but I know it should run better than it currently is. Thanks again for all of your help!!
you need a choke, period :thumbsup:
 

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An old fashioned hand choke fixed mine.
I give the accelerator a couple of pumps, pull the choke all the way out, start it up, push the choke about half way or so back in and go.

The only problem is once in a while I forget to push the choke all the way back in. :(
not being a smart a&& dean but i dont think a lot of people know what a god ol fashion hand choke is :beers:
 

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I had a 650 DP before I switched over to EFI. It was always really cold on start ups, even in the summer, but not as bad. I normally would pump the pedal 3 times, then crank it over. Typically would work well, but I would have to hold my foot on the gas for a minute or two. I had a manual choke hooked up, but it would get stuck, causing the motor to be choked when driving around. Hence why I stopped using it...
 

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66 El Camino 57 Chevy pickup 2004 Tahoe
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there is that.....
 
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