Merry Christmas! Now for my issues. The car is a 1971 L48 with a holley 4150, dart IE heads, crane came, and some other not so important upgrades. I'm not sure what my problem is, but here are the symptoms. Only the left headlight pops up and now that its up wont go down, wiper door won't open, engine runs VERY rough and rich, wants to die no matter what temperature the engine reaches, and I seem to not get any response out of my idle mixture screws. I have played w/ the screws in the past to even out the banks and tune the engine, but adjusting them now seems to have NO effect on the engine.... won't even change pitch when turned to the extremes. My thoughts.... well, I figure the two problems are probably related, afterall vacuum pressure is essential to the proper function of a carb. Something to do w/ the float? Vacuum leak? Grrr! Better not be any of that.... just paid alot of money only 6 months back to have all my vacuum pumps and lines replaced. I've gone ahead and pulled out every sparkplug. They were carbon/sooty, but otherwise fine...... black as night though. Cleaned em off w/ a steel brush and put everything back together, still no dice. Any help..... I've reached a wall w/ this one.

 

ttt Also, the carb seems to be dripping gas from the secondaries at idle.... not sure if this confuses anyone even more.

 

The first Item is the headlight.
You need to figure out if it's vacuum related or an mechanical Issue.
Basically you have one feed vacuum line connected to the big cylinder looking thing behind the bumper area. From the feed tank it supplies vacuum to the individual light assemblies. There is also the control vacuum line that determines what position the main vacuum is feed. The control valves are located behind the head lights.

Check your vacuum lines. Sucking on the control line will move the valve from one position to the other and bring the lights up/down. Mech issues are a little harder. Reach in there and move the headlight manually and see if anything is binding. Watch the paint. I would bet it being the vacuum lines as the engine is also displaying leak symptoms.]

Good luck
Dave...

 

Thanks Dave. I just got done pulling the needle out to make sure it wasn't stuck. For safety, I also set the idle mixture screws 2 turns out from full in.... since I'm not getting any response from them I figure its safe to set them where tuners say you should start when tuning a new carb. Time to crank her up and see if the float needs adjusting. If none of these fixes can solve my problem, I'm gonna start pulling off and plugging the vacuum lines at key points to try and isolate the leak.... since I figure it can really be anything else. Also, if anyone else has an opinion on my problem, please chime in!

 

It sounds like you need to go through the vacuum system before you try to adjust the carburetor.

http://www.ecklers.com/product.asp?p...66&dept_id=224

BigBlockk

Later.....

 

There is something wrong with the carb if its dripping fuel into the secondaries at idle. Either the float is out of adjustment or the needle and seat aren't sealing. Be sure the secondaries are completely closed at idle also.

Good Luck, Paul

 

Thanks for the help guys. I went in and pulled the needle out. Tapped it, fiddled w/ it..... (first time I've ever gotten this intimate w/ my carb, prolly increased my carb knowledge 20 fold since yesterday!), then reinstalled it. I tightened the screw down, and lowered the needle w/ the adjusting screw. However, I made two mistakes before starting the car. First, I didn't tighten the adjusting screw low enough, so the fuel level was well above the eye hole that is used to properly adjust the float. Second, I started the car w/ the screw that covers the eye hole on....... lol. Long story short, I took the screw off the eye hole and gas started pouring out of it in pumps...... like a man bleeding from one of his primary arteries! Thankfully that was all that happened. I did notice, before removing the screw over the eye hole, that my secondaries were no longer dripping!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!! Yea..... I'm that excited I'm hoping this means the problem was a stuck needle. I've since tightened the adjusting nut to almost the lowest fuel level and cleaned up the mess I made. Once the fuel dries I'm gonna start her up, w/ the screw covering the eye hole off, and slowly raise the fuel level until it just begins to trickle out. The engine also sounded a hell of alot better, not to mention I wasn't creating a fuel air bomb out of the development w/ my exhaust! However, my headlights and wiper door still don't work. Which brings me to a question for you Vette heads out there!

I'm gonna go through and systematically eliminate my potential vacuum leak. I want to start at the top and work my way down.... mainly to ensure the engine is tuned w/ the correct vacuum pressure..... that being said:

If I'm going to plug one of the vacuum lines to insure that the leak is no longer in the loop, what is the very 'first' line I should plug? Right after the carb? Tank? Perhaps something to plug while tuning the carbs float and idle mixture...., a way to ensure I have correct vacuum pressure for at least the time being. I figure if you can help me figure the first, most essential spot at which I can plug the system, I'll tune it there then go back after she is tuned and work my way down through the rest of the vacuum system, systematically unplugging and plugging various odds and ends til the leak is located. Thanks again for all the help guys!