Steve69 wrote:

Hey Guys,

Last year my 347 engine was running rich.  I'd saw a little black smoke from the exhaust when I stepped on it and the MPG were really bad.  I connected a AFR gauge and that confirmed it.  Other than that, the carburetor had some fuel boiling when it was hot but ran great.  Idle great and no bog or issues.  Has all new spark plugs and ignition. Total timing was set at 34 degrees.  It was actually running quite well after I got some of the bugs worked out with the ignition.  

During the winter I thought I would drop the carburetor two jet sizes since the fuel bowl would be empty because of sitting all winter.  I pulled the top of the carburetor and floats.  I left the fuel line connected on the top.  Had to move the top a 45 angle to disconnect the choke lever.  Installed the new jets.  All straight forward.
  
I went out to fire it up and it wouldn't start.  There was just cranking.  I checked the spark and that was good.  I put a little fuel in the carburetor to make the fuel pull up quicker from the tank.   Got it to fire but ran bad.  I had to hold and pump the pedal to keep it running.   I took a look at the fuel bowl site glass and could see anything.  I moved the car around a bit and fuel lever appears to be above the glass circle.  I also noticed a puddle of fuel on the intake manifold below.  I'm thinking the fuel must have leaked from the top where the gasket is to seal the top of the carburetor.   Both fuel bowls were over the site glass top.   I didn't expect taking the top off the carburetor to replace the jets would have affected the fuel bowl adjustment.  

Should I try adjusting the floats to drop the fuel lever down?    Am I missing or overlooking something?

Thanks for the help!
Steve69

 

 
If your fuel level is to high then the needle seats are stuck open.

They are stuck open from dirt or something getting in there and they could simple be bad.  Today's gas is very hard on rubber products and the part that seals on the needle seat is rubber.   Most likely will need to overhaul with a rebuild kit.

John Ha wrote:

Steve69 wrote:

I pulled the top of the carburetor and floats.  I left the fuel line connected on the top.  Had to move the top a 45 angle to disconnect the choke lever.  Installed the new jets.  All straight forward.

I moved the car around a bit and fuel lever appears to be above the glass circle.   

I wonder if, when you removed the top of the carb with the fuel line attached and tilted it to disconnect the choke lever, the floats moved from their normal pivot points and are now jammed so they can't move.  Did you check to make sure the floats moved up and down freely before you put the top of the carb back on?  

   I had to put the choke lever in a slot with a really small clip.  I think I got that together right.  I did make sure the floats moved properly up and down without any restrictions when I had the top off.   
 

OK.......when you first started (and when there WAS fuel in the bowls) was the gas up to the sight glass or a little lower?
After the jet change....is the fuel up to the sight glass now?
IF the float level is TOO low that COULD be the reason ALL the fuel boils out!
The gas IS crap butt....ALL the fuel boiling out is weird !
Not being familiar with your carb (and no pics) I'm not sure what it looks like.
When you take the top off do the floats come off with the top? OR...
is it like the old Motorcraft carb where the float is in the body of the carb?

My guess is.......the needle & seat were dry during the winter and got dried out and now they leak.
Now that you have them submerged in 'crap-gas' maybe they have softened and  will seal 
IF not...replace and play with the float level.
6sally6

Thank for all the wealth of knowledge.  Ill take a closer look at it this weekend and try some of your suggestions!   Thanks Again!

Steve69

It is easy to pull the carb and do the work on the bench.  Consider pulling it, cleaning it good and putting it back.  Probably your needles and seats are fine, just inspect them and clean them.  If your carb to intake gasket is stuck, then coat the new gasket with grease on both sides before installing it to prevent it from sticking in the future.