Thanks for the info - with my car, there seems to be no rhyme or reason to when it decides to stall. Usually does pretty well on longer road trips, though . . . .

What is a carb spacer?

 

Well, the fuel filter came in, and before I installed it, we gave noonie's suggestion a try. There was some very tiny specks floating around, but for the most part, the gas looked pretty clean. Installed the fuel filter - not too shabby for a computer geek, huh? Test drove it - it started out rough, but then it "coughed" (back-fired) and ran just fine afterwards. We'll see if it lasts . . . . .

Question - what is the round black object with the two wires above and to the left of the fuel filter? And should it feel hot when the engine is not?

 

its an electric choke that contains a tiny heating element and a bimetallic coil/thermostat. that linkage rod actuates the choke flap.

the red wire should only have 12v with the switch on

 

Nice work geek
Nice clean job. The Edelbrock filter has a replaceable element so you may want to order a spare in the case that the new one gets plugged up quickly from crud in the gas tank.

The black part is the choke controller as Rusted stated and it should be warm if it's working correctly.

Take some pics of the engine bay from all angles and post them here so we can look for other issues.... we like to pick peoples cars apart ... honestly, post some pics, so we can see what else may be going on.

 

Suzie-Q, You say it does better the longer you drive it, Possibly your choke may either be set too tight(the black thingy that gets warm)When the car is stone cold you should be able to press the gas pedal down once and the choke closes, with out cranking the car pull the air cleaner and see that the choke butterfly closes fully.The choke should snap closed when the gas pedal is depressed fully.Then cwhile watching the choke butterfly have someone crank the car, if you rev the engine after starting the butterfly should open partially.As the car warms up the choke should open fully, if it does not the choke maybe too tight or the choke isn't "pulling off".The longer it runs the better it runs makes me think you have a choke problem.A couple of other things you might outa check is the fuel line from the frame to the fuel pump should have an "S" hose it is a molded hose that sometimes gets replaced with a generic length of hose that tends to close up and would give you stumbles and surging at highway speeds.Also make sure that the fuel tank is vented properly, you can easily check this by loosening the fuel cap and going for a ride to see if the problem goes away.In 1968 all vehicles were equipped with a carbon cannister to vent the tank.Hope this helps out.

 

Thanks for the advice on the choke. The problem is it was HOT, not merely warm. The engine was cold, but the key was in the "on" position - I had cranked it a few times to dump some gas out (noonie's suggestion) and not turned it "off." It was in the "on" position for awhile. Should it get that hot?

I will post pics of the engine compartment tomorrow - didn't have time to take any today. We went to the Corvettes Against Breast Cancer event at the Atlanta Motor Speedway. Didn't take ours out on the track, but it ran GREAT the entire day! But, then, it does that for awhile . . . . . .

 

Yes, it's a thermal spring and it reacts to heat which is generated by the current supplied when the key is in the "on" position.

Your fine.

 

Thanks for the advice! We've actually checked the choke, and it works fine. We've even pulled the breather off when it's acting up, and it's working as it should. Our problem usually happens after we've driven it awhile and then stop for a break (not a short break, but like for lunch). It'll start running rough - sometimes it feels like it's surging and other times like it's missing. It will also stall out (or try to) whenever we come to a stop.

Haven't checked for the "S" in the hose - will do that tomorrow! It's the original fuel line (except that short rubber piece coming from the carb), so it's probably there.

Don't think it's the gas cap - when we bought the car, it had a locking gas cap. Only problem was the guy lost the key (!) and had drilled the lock out. The gas cap just "sat" on the tank, so it was well ventilated!

 

Look at all the white flakey stuff that looks like bird****, around the intake bolt behind the new fuel filter and also on the sides of the carb.
Chances are very high that the inside of the carb looks similar and your needle and seat are probably compromised a little too. Looks like it has sat for lenghty periods around a lot of moisture.
The rough running after letting it sit for an hour together with the pic could be a flooded intake together with a dry fuel bowl, especially if it straightens out after a few minutes.
Probably time for a good cleaning and kit in the carb.

Either that or drive it a lot and see if the crud will wash out.

 

This is a very good point, if the car did sit alot before suzie-q got it that crud could be inside.Maybe time for a carb kit and one of those gallon cans of carb cleaner.One old trick we used to do on a carb that we suspected of this was to rev the engine up to about 1500 RPM and take a shop rag and choke it down(making sure none of the rag gets sucked in this wil pull more vacuum thru the airbleeds and sometimes dislodge small debris caught in a passage.Spray it good with gumout first.Suzie it sounds like your are capable of putting a rebuild kit in a carb.If you can take computers apart and back together I'll bet you could put a whoopin on that carb.get your manual a carb kit,and the cleaner.The rebuild kit will show a break down of the carb and will renew the stuff that usually gets bad, needle ,seat check float adjustment.They usually even have a small measuring stick to set the float.

 

Thanks for the info! Yes, I think the carb is due for a cleaning as well. However, 74/L82/4spd, I think you may be giving me more credit than is due! Looked up the instructions for the rebuild kit for that carb, and was kinda concerned because it was 12 pages long. Realized that 2/3 were in a different language and only 3 applied to me. Whew! But what I read might as well have been in another language Honestly, guys, is this something a newbie should tackle??? I guess if I screw it up completely, I can take it to a professional, right?

 

Forgot to mention, I did get an extra replacement element when I bought the filter. Here are the pics as promised - pick apart at will!

#1


#2


#3


#4


#5


#6


#7


#8


#9


#10


#11


#12


#13

 

Suzie, Your carb looks clean inside from the pics.Did you check your S hose from the frame to the fuel pump?Also this may sound crazy but yourI coil, I replaced my coil as a step towards fixing a miss that I had.I noticed the replacement coil was getting hot, but no otger problems until one day it stalled out on me in I-75 southbound morning traffic.The engine restarted and I was thinking what in the world could have caused it to die like that.Well that evening on the way home the car was running great until about a mile from home it died and would not restart.I had my son bring me some tools and the old coil.I ended up putting the old delco remy on and it cranked right up.So just for grins check and see if the coil is getting hot.Also once again make sure your fuel tank is venting, cause if it happens after it runs awhile then you shut it off and on restart could indicate your fuel system is drawing a vacuum.And yes I think you can handle the carb rebuild(if you can take computers apart and put them together)but I think I would hold off until you make dang sure your fuel supply or ignition system isn't the problem.You say that the car runs good sometimes usually the carb is going to give you problems all the time if there is a problem with the carb.Your carb has different circuits in it.You have an idle system,you have a transitional when the accelerator pump shoots extra gas when you mash the pedal and then a circuit while cruising down the highway.You also have the choke system for cold starts.usually when the carb has a problem it shows specific to that circuit.I hate Driveability problems.

 

Suzie, I see a few minor things wrong. Missing hold down screw in the coil bracket.
A flat braided ground strap that is not connected in pic#2 behind the 4 spark plug wires that are under the chrome shielding.

The fan shroud seems to be missing the extension (very dangerous for your hands and also can effect cooling)
Your throttle cable bracket looks a little out of position, I'm wondering if your getting full throttle from the pedal. With the air cleaner removed and the engine off, have your husband push the gas pedal all the way to the floor and then see if you can push the linkage back even further with your hand than the pedal has pulled it. If you can then it needs to be adjusted so you can go even faster

The pad on the block where the vin# is stamped seems to be painted over in black (between the wide area of the two red hoses in pic #10)

Maybe it's just the camera angle or maybe it was painted over to protect it from rust, who knows.

If the car is as a matching numbers car (original engine among other parts) then the number on that pad should match the vin# on the drivers side windshield pillar.

It would be nice to know what the number reads so you will know if it's the original engine or at least know if it's a Corvette engine or not.

I don't see anything major to worry about.
Just be careful of that fan when your under the hood and make sure it's running cool enough.
200 degrees or less.

 

Thanks, guys, for all the suggestions/comments! Dragged my hubby out in the rain (well, mist!) to go through your lists!

74/L82/4spd, yes, I did check the fuel line and that "S" curve is there! We did replace the coil - one of the first things we replaced - but haven't checked to see if it gets overly hot. Will check it next time we run it. I honestly don't think the problem is with the gas cap - we drove it for awhile before we found a replacement cap. We then replaced the replacement with a locking cap, and the problem has happened with all three!

Bob, there's a reaon why that screw in the coil bracket is missing - it's because the replacement coil is too big!! Couldn't find the ground strap you referenced - the only thing we could find was a rubber strap that bundled the spark plug wires together. Should there be a ground strap? Could you elaborate, please? We do need to get a complete fan shroud - it's on my list! Didn't realize it could affect the cooling that much. Our car usually runs, especially on hot days, over 200.

Thanks for pointing out the throttle cable issue! I had bought those Fox All-Weather Boots for the floorboards. Seems that the one on the driver's side is hampering the gas pedal - there was about a half inch difference. Pulled the "boot" out and tried it - there was just a slight difference this time, but one we'll fix. We'll also modify the "boot" so it doesn't interfere with the gas pedal. Can't have anything interfering with our need for speed!

Looks like our engine is an original! The VIN is the same, although the last number is very, very faint. And, no, the VIN wasn't painted over - that was a very thick layer of grease . . . . I haven't done much in the way of cleaning the engine (as if you couldn't tell!) until we get all the "issues" out of the way. I did clean off quite a bit around the valve covers while I was working on the fuel filter after noticing in a picture that it looked very "wet." We haven't pulled the valve covers off yet - kinda worried about what we'll find when we do . . . .

Ordered my carb rebuild kit - should receive it in a few days. Might save that task for a long weekend . . . . . . .

Thanks again!

 

You don't need a "complete shroud"
The proper extension is approx 2" wide at the top and bolts on to the existing shroud.

From the overall general apperance of the underhood, a good cooling system flush would be beneficial.

Check your ground strap connections too. Won't hurt.

 

Thanks, noonie! Didn't know I could buy just the extension for the fan shroud.

Haven't done a cooling system flush yet - will add that to my list of things to do . . . . . .

Where can I get more info on the ground strap connections (locations, etc.)?

 

The coil isn't too big, it's just a cramp to get that screw back in. If you use a big pair of channel lock pliers you can squeeze the bracket enough to get the screw in... no big deal right now.

Your right. That is a plastic wire loop, I thought it was a ground strap from the pic...

Post the 5th digit on the engine ID pad, it should be either a J or a T. This will tell you if it's the L-48 (base engine) or the L-82 high output

Let us know!

Heres a site where you can see what your car was shipped with from GM by using the vin # and trim tag which is on the inside of the drivers side door.

http://www.100megsfree4.com/corvette/1970/vet74.htm

EDIT*
This is strange
The site I linked to states that the base engine was (RPO ZQ3) not L-48...Is this correct guys?
I have never heard of the Standard Engine refered to as ZQ3
It also states that the trim tag is located on the engine side of the cowl rather than on the door. hmmm....

 

Suzie,I am unsure of all the straps,I know that there is on ground point on the firewall.there is a ground strap in the starter area that bolts to the motor mount bolt.do a search on ground straps here on the forum you will find lots of info.Let me know if you get stumped on the carb.If your in marietta, I am not far from you, I am closer to acworth than dallas.So we are neighbors.When you go to put the kit in make sure you get a good carb cleaning solution,you will also need compressed air to blow the passages.

 

Well, already know that my engine is the "base" model . . . . *sigh* . . . . but, hey, it's still a Vette and it's MY Vette!!