340 not running anymore...Help Please?

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Holleys don't "sit" well. I advise to rebuild them at least every two years. The needles and seats are easy to get crud in and stick and I think that's what's happening. Change the fuel filter (install a steel body stock type...no clear or plastic ones). Pick up the nylon needle and seat gaskets for both bowls. Pull the needles and seats and blow them out with carb clean. Then re-install and set the floats. I think it's flooding out.
 
To everyone who has given their advice, thank you!!!! I now have a pretty good idea of a logical A-Z to start on in the morning. It'll probably take all weekend, if not longer, but I'll post what I find as I go thru my list.

For all y'all who have attempted to hijack this thread to argue politics, could you please take it somewhere else? I've been without transportation since November, and your politics aren't going to fix my car. If you aren't posting something productive I kindly request you don't post at all.
Thanks
 
rednesss said:
Please astound the crowd with a compelling reason for crapping up our gas with 10% or more of ethanol????
Click to expand...

Well back in the early 90's the government mandated only oxygenated gasoline be sold in the US in areas where smog was an issue. Oxygenated gas burns more completely thus reducing emissions.

This was accomplised by adding MTBE (Methyl Tert-butyl Ether) to the gas. MTBE was selected because it was cheap, but by the mid 90's the MTBE was being found in drinking water so a switch to the more expensive Ethanol was made.

I wouldn't know if Ethanol craps up the gas or not i have been using it for about 15 years now and don't recall any changes in the way my cars ran back then when the switch over was made. I do recall some folks had issues with starting there cars in the cold weather but I never did. I don't recall any measurable change in mileage either.

Right off the bat one advantage of Ethanol in the gas is higher octane. Take 91 octane and mix in 10% Ethanol and you have 93 octane. The other advantage is if you live in an area with wide and rapid temperature changes moisture condensation in the gas tank is a real issue. Ethanol binds up with the water so you do not get freezing or shitty running when a slug of water is ingested into the engine. Back before Ethanol was added everyone would add a bottle of dry gas with each tank full in the winter, drygas is alcohol. I don't do that any more because it is already in the gas.

One thing that is more recent is labeling of the gas pumps. With the introduction of E85 and flex fuel vehicles there was confusion over what you were buying so regulations were changed that required the pumps to be clearly marked. So you have likely been getting E10 fuel for years and just recently have been made aware of it with a label on the pump.
 
More questions.....

1. I'm not really familiar with working on carbs so I downloaded the instructions for my carburetor from the Holley website and started trying to figure out what is what on it and I still am at a loss as to how to tell if the floats are stuck etc. Can anyone point me in the right direction for some instructions?

2. While I was identifying the parts and what they did, I came across something. The zip-ties are attached to a level that is part of the vacuum operated secondary throttle mechanism. The zip-ties appear to override the vacuum and open the secondary throttles whenever the throttle lever moves. Is this some sort of vacuum to mechanical override? Is there any legitimate reason that I should have these zip-ties on there?

Secondary.jpg
 
Cut all those zip ties off. Someone tried to make your Vacuum Secondary carb work like a double pumper and that just doesn't work.

Makes me wonder what else they have going on with the carb…….
 
Hmmmm, when you say din't run quite rite I'm thinkin float level is to high, and oil fouled plugs.....black smoke out the tailpipe when it does fire up say's floats to high.....another common problem is sucked in intake gaskets...happens all the time when intake is not retorqued....but will have blue smoke out the tailpipes....
 
Ok, zip-ties are gone. As for the float levels, the Holley instructions for checking and adjusting the float level are:

FLOAT LEVEL CHECK AND ADJUSTMENT:
Primary and secondary float adjustments are set at the factory, but variations in fuel pressure could cause a change in these
settings. The following procedure shows how to make these adjustments:
1. Start the vehicle.
2. Observe the sight plug for the fuel level. If none is seen, the level is too low. Fuel should be even with the bottom of the
sight plug hole. If fuel comes pouring out of the sight hole, the float is set too high.
NOTE: A properly set float level will have the fuel level located at the bottom edge of the sight hole, as shown by the line in
Figure 12.
3. To adjust, shut down the engine.
4. Loosen the lock screw on top of the fuel bowl just enough to allow you to turn the adjusting nut. Hold the screw in position
with the screwdriver.


Since the car won't run I can't follow these too well, but I can say that the fuel level in the sight plug is where "figure 12" shows it is supposed to be :munky2:
 
On the bowls at the front and rear of the carb there should be screw in brass plugs about 1/2 way up. You remove these when the end is running to set the float level. The gas should just barely dribble out the hole. Holley now sells (and many of the new carbs have them) see though plastic plugs so you can just take a peak to tell the level.

Chances are good that they removed the spring from the secondary diaphragm on the other side of the carb. Unless the diaphragm assembly has a black two piece cover you will need to remove the assemble from the carb to get the cover off and check. Also, make sure the diaphragm it self has no tears around the edge. In one corner there is a hole that should have a check ball in it, that's another thing people remove that think they know more than Holley.

The Holley instructions you down load don't help much once you get into the carb. The instructions that come with the rebuild kits are better, but the best thing is to get a book. This is the one I have and it is very good. I got mine at Borders but Amazon has it too for less.

51Y67RpDLsL__SL500_AA300_.jpg
 
The car doesn't necessarily need to be running to get an index. You can crank it over and the fuel pump will either quit pushing fuel when the needle closes or it will flood over. This however is dangerous as any spilled gas will only need a spark to ignite. I would remove the bowls and visually check the needles and seats for any debris, a small speck will keep a needle from seating. While you have the float in hand put it in a tray with some fuel and see if they float or sink. They should float. After that reinstall the float and turn the bowl upside down to make it go against the needle seat and you'll be able to sight it close.

Dave

And what Dave (dgc) typed while I was typing...get a book..
 
Well, I pulled the vacuum secondary off and there is a small tear in the diaphragm. So I got to the store Friday night after school and tried to order a rebuild kit and a diaphragm, but they are back-ordered from the factory. While at the store, I picked up a timing light, inline spark tester, and the Holley book you guys recommended. I had a wedding Saturday, so I planned on getting into the car on Sunday. With a wonderful offer of help from replicaracer43, who happens to live in my area, I just knew that I would have some success in getting this sorted out. What I wasn't planning on was my boyfriend... He is a wonderful boyfriend, and had planned a wonderful day to celebrate my birthday. So, I wound up at the drag strip in Mooresville for my school's annual drag races. So much for accomplishing anything on a weekend..... I got my fingers crossed that this week goes smoothly and I'll be posting some results on here soon :)
 
Holley sells a spring kit to taylor the opening of the secondaries,Pick up that kit since you have the diaphram apart already.depending on what gears and convertor you have will determine what spring you need to install,the lightest springs are for lighter cars with looser cars and tall gears where the heavier springs for heavier car with stock type convertor and airplane gears
 
Airplane gears? I googled and found this airplane dog, but no airplane gears.....
Airplane%20Dog.jpg


Hehe.... but, seriously..... I can order the spring kit. It seems like a good idea since I don't have much faith in the way the past owners set this car up. I would like to know more about the different gears you are talking about so I can make an educated decision on my spring selection. Thanks
 
She Devil said:
Airplane gears? I googled and found this airplane dog, but no airplane gears.....
Airplane%20Dog.jpg


Hehe.... but, seriously..... I can order the spring kit. It seems like a good idea since I don't have much faith in the way the past owners set this car up. I would like to know more about the different gears you are talking about so I can make an educated decision on my spring selection. Thanks
Click to expand...

LMAO! Well, I've been around on this earth for well over 40 years and never heard of "airplane gears". Wags, can you explain?

Shedevil, I like your style and it sounds as if you are on the right track. I'm thinking that Wags meant to say either "Low Numerically" or "High Mechanicaly" as cars that cannot rev quickly will bog if the Vacuum Secondary spring is too light. In other words, if the secondaries open before the engine can draw enough air through the venturi to pull fuel, it will experience a lean bog. Start with the strongest spring in the kit and work your way lighter till it gags when flooring it from a dead stop.

Holley has a wealth of info on website that makes great bedtime reading. http://www.holley.com/TechService/ Bone up on your carb skills there.

I also want to congratulate you on such an intelligent and composed thread. You'll do well in life and I wish you luck. Now, I am going to steal that picture for use sometime in the near future. :clock:
 
Update!!!!
Finally got my rebuild kit and started rebuilding my carb. Got it off the car, got the bowls off, and hmmm...... what in the world are those funny little screws. Spent the next few hours looking for a funny looking screwdriver to fit the funny looking screws then finally gave up and made a plain flathead work. I got it all apart, and have matched up all the old pieces with their new replacements and low and behold I have an unnerving number of pieces left over. Gonna look through the book tomorrow and make sure I haven't missed anything and then cross my fingers and start putting it back together.
Wish me luck! :)
 
The rebuild kits fit a number of different carbs so you will have a bunch of parts left over.

One thing to double check is the gasket that goes between the metering block and the main body of the carb on the primary side. Some of the kits have two different ones and the difference is subtle. About one third of the way down from the top of the gasket and centered left/right will either be a hole or a rounded notch. If you use the wrong one fuel will leak directly into the main body well and will flow over every where. Most of the newer carbs use the one with a hole.
 
I read somewhere that todays gas only lasts about 30 days before it seriously starts to degrade.

Your problem does sound like the choke is not working properly.
 
hmm.... the choke could be a problem, since it doesn't seem to be hooked up at all.
Correct me if I'm wrong, but I think the car originally had an electric choke. This carb has a manual choke, but it was never attached to anything. It never had any issues before this tho, so....
 
I think the "72" 340 was the last strictly mechanical well choke. If all else is OK you should be able to pump it a couple of times and it should fire. Make sure the manual choke is full open. Also when running the choke can get sucked shut at the most inopportune times. Keep an eye on it.
 
At the very least you could pick up a cheapo choke kit at the local parts store and install thet. Then you'd solve two potential issues. You would have choke control which really helps our old MOPARS, and then you also cancel out the chance of the choke beig sucked closed. Im wondering if thats not whats happening along with the fact that it sounds like the carb needed rebuilt anyway.
I have my Eddy carb that I went through something similar with recently. I actually adjusted the Secondaries to kick in a tad later than it was when I started. I have been driving it on the Interstate a lot and it has helped to not use as much fuel, cause the secondaries arent so far open, or may very well not be used while Im cruising at 65MPH.
Def. sounds as if you have fuel issues though.
 
You can buy an electric choke kit from Holley to put on the carb if you are so inclined. At the very least make sure the choke is wired to stay open. If it was vibrating partially closed that could have been the source of some of your issues.
 
***UPDATE***
Things aren't progressing very well. To start, I could swear the old gaskets were attached with super glue and cleaning was a bear! Then I got to the installation of the power valve and found that 3/8" inch pound torque wrench + 1/2" 1" socket= back to the store..... AArrrgghhh!!!!
Ok, so everything's clean, got the power valve installed and torqued to spec, primary side looking good....then there's the secondary side.
In the Holley book, page 116, the instructions are very simple. They state, "When reinstalling the secondary metering plate, first the contoured gasket is placed on the plate surface, then the thin metal plate is placed on top of the contoured gasket"...... ok, thin metal plate....where is the thin metal plate? I didn't remove a thin metal plate, there's no thin metal plate in my rebuild kit.... Why don't I have a thin metal plate?
So, is my carb supposed to have a secondary metering body plate?? If so, why doesn't mine have one?!?!?
 
She Devil said:
***UPDATE***
Things aren't progressing very well. To start, I could swear the old gaskets were attached with super glue and cleaning was a bear! Then I got to the installation of the power valve and found that 3/8" inch pound torque wrench + 1/2" 1" socket= back to the store..... AArrrgghhh!!!!
Ok, so everything's clean, got the power valve installed and torqued to spec, primary side looking good....then there's the secondary side.
In the Holley book, page 116, the instructions are very simple. They state, "When reinstalling the secondary metering plate, first the contoured gasket is placed on the plate surface, then the thin metal plate is placed on top of the contoured gasket"...... ok, thin metal plate....where is the thin metal plate? I didn't remove a thin metal plate, there's no thin metal plate in my rebuild kit.... Why don't I have a thin metal plate?
So, is my carb supposed to have a secondary metering body plate?? If so, why doesn't mine have one?!?!?
Click to expand...

Not having the carb in front of me I couldn't say if it supposed to have one or not however from what it sounds like YOU have a Holley book in front of you and the carb, Are there not complete breakdown pictures of the carbs.???? To be able to tell you if it's missing something. How about posting pictures?
 
The this is a picture of the pieces as shown in Super Tuning and Modifying Holley Carburetors by Dave Emanuel. The exploded view in the Holley instructions show all the same pieces.

book.jpg
 
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