Corvette Forum : DigitalCorvettes.com Corvette Forums banner

1 - 2 of 2 Posts

·
Registered
Joined
·
179 Posts
Discussion Starter #1
I have a two fold problem and they are related. The first is when Ishut the car down when it is hot I still get the fuel percolation. You can watch the fuel ooze out of the air bleeds and the squirters after shut down. It is slowly soaking the primary only side of the carb. Makes the car a bear to start after sitting for 5 minutes then when it does start is sputters and chokes until it clears itself. Both float levels primary and secondary are the same. Right at the halfway mark. Should I go lower and if so how low can you go?

I am also getting some sputtering just off idle. It idles fine but when you pull away under normal acc. it will sometimes sputter. Now I put in my LM1 and it shows it dropping down in the high 10s when this happens. It will go back up to high 12s pretty quick but I have had it die on me twice recently. Starts back up but it cranks like it was flooded with fuel. I am running a 6.5 PV and it is idling right around 7 to 8 inches of vacuum. Just crack the throttle and it goes up to 12 inches. I cruise at about 8 to 12 inches and sometimes more vacuum. Should I drop down to a 4.5 PV.

I posted about FI on the car but that is going to have to wait. There is no reason I should not be able to get this carb running decently. Under full throttle is just screams, no missing no hesitation, you hit the loud pedal and all he$$ breaks loose. The AF is running right at 12 to 12.5 under full throttle so it should be jetted good. The dyno run last winter confirmed this also.

The car is a 72 Vette with a 385 SB, Tremec with 3.70 gears. Afr 195 heads and a solid 252/260 @ .050 with a .540 lift. 10.75 to 1 compression. Dynoed last winter at 409 RWHP. Runs good at WOT just have some part throttle problems. Carb is a 825 Mighty Demon sitting on top of a Victor Jr. intake
 

·
Registered
Joined
·
130 Posts
I had the same problem with percolation with a Speed Demon on an Edlebrock RPM manifold. A one inch phenolic spacer uder the carb along with dropping the float level to the point where you can just start to see it at the bottom of the sight glass was the fix.
I run 1/4 inch composite gasket/spacers under both Demons on a 6/71 blower and still no perc. problems.
 
1 - 2 of 2 Posts
Top