gas smell

[JohnZ]

The '70 LT-1 had a thin carb gasket, then GM changed it to a thick insulator gasket for the '71 and '72 LT-1 to reduce fuel percolation problems. Dr. Rebuild has the correct thick insulated gasket you need (their #3726123, $18.00).

 

[tonyk72]

Already got it on order...
The Doc describes it as 1/4" inch thick fiber...
My current gasket looks like 1/8" rubber...
will install it this weekend along with some other goodies...

 

[Rich80]

Good thing you found it. Mine was dripping at the fuel filter and would never leave a puddle cause it would evaporate off the manifold till one dat I had the air cleaner off and saw it drip while it was running. I have to get a fire extiguisher for that thing!

 

[Alwyn678]

I would go ahead and get the pheolic spacer anyway to keep the gas nice and cool in the carb. Cool gas = More horepower

 

[tonyk72]

thick gasket = no luck

Well I got the nice fat gasket from the Doc installed...no luck, I can still find gas pooled up on the intake the next morning after I take it out for a drive...
The next step is to check the fuel bowl levels...
From what I know, on my Holley 780, if you unscrew the little nuts on each of the fuel bowls and no gas drips out, the level is not too high and should be OK...
This is how mine is set...should I drop it lower?
I'm hesitant to have the carb rebuilt as the previous owner said he had it done in the past 2 years...
The other option is a heat shield of some sort...wasn't there one used on the 70 LT-1's?

I'm having a mechanic come over in a few days to help me with some other issues..I'll have him take a look at this too...

 

[Brettmc]

You might have a cracked baseplate. You might want to take it to a Holley rebuilder (or someone local that knows Holleys) and quiz him on where the gas might be coming from. If no gas comes from the sight plug when you remove it, your fuel level is fine. Have you looked at the carb while the engine is running? Try this: Spray the leak area with WD-40 or carb cleaner. Fully clean the area so that you can see where a leak might originate from. Turn on the engine and look for the leak.

Brett

 

[norms72]

I had a similar problem with the gas pooling on the intake. The car had sat for a while and when it was finally started, it left a puddle under the carb. It seemed to be coming from the primary pump on the Holley (older model, mech secondary). After fiddling with it for a while it stopped and hasn't done it since. Just food for thought. I also found a seepage problem at the rear beside the frame. Rebuild time. :cry


:gap

 

[luvmy73]

Well, if you look closley at the pic I attached, right around the intake manifold bolts, there is a small pool of oil. At first I thought the oil was coming up through the bolts. I put some thread sealer on the bolts and torqued them to spec.
This leads me to my next question.
How diffucult is to remove & replace the gasket?

The area where your leak is coming from is a common place where quadrajet leaks occur. What happens is that the fuel in your carb is boiling after shutdown, and this forces the fuel out the main discharge nozzles after the car sits for a few minutes. This fuel hits the thottle plates and siphons out the sides of the throttle shafts. It then pools right where you indicated. There is no solution for this unless you want to run some good 100-octane race gas at $4.50/gallon. However, you can improve the situation by dropping your float level from the factory setting of .250" to .375". This improves it quite a bit. I run the .375" setting on all pre-'75 street-driven carbs, and only use the .250" setting for racing.

Many vette owners also expereince this leak if they flood the carb before start-up. You can try to replace the gasket, which is as easy as removing 4 bolts, and this may solve the problem as well.

Mike.