Black Smoke, have to screw idle/air all the way down

[geezer#99]

Originally Posted by ubtripn

I am planning to downsize the carb when I have the dough. Just wanting to do what I can right now to help in any way.

I put a fuel pressure restrictor on last night, advanced my timing (we are at about 2100 feet) adjusted the idle but the air/fuel screws still need to be turned all the way down BUT I did get a huge improvement in two areas. No more black smoke except a small puff when I stand on it and a VERY noticeable increase in power across the board. It runs like a top but I know now that I am over-carbed. I wish Edlebrock still made the Rochchester (sp?) like carb. I want very small primaries. Anyway, 600 or 650 is my plan in the future.

All I did was put a $40 dollar Mr. gasket fuel pressure restrictor in line set at 5.5 but I wonder if I turned the fuel delivery down some if it would bring the idle/air screws into play. Eddlebrock says to go 6.5, it doesn't need it. I do not believe I am flooding the carb anymore and since it is running strong and the temp is dead steady maybe I should leave it alone. I don't know. But there has been improvement.

When I ran my dual quad I used a Mr. G regulator set at 3.5 psi which was minimum. Fuel pressure ran a little higher at 4.5.
Don't worry about running out of fuel at that pressure. Mine was good with 2 carbs right to 5500 rpm and 120 mph.
The key to getting your mix screws responsive is in closing the throttle down to cover the transition slot. Might be hard to do on your carb.
With increased initial you'll likely need to limit your mechanical and vac advance.
Good to see (hear) you got it crankin'!!

[geezer#99]

Originally Posted by ubtripn

I am planning to downsize the carb when I have the dough. Just wanting to do what I can right now to help in any way.

I put a fuel pressure restrictor on last night, advanced my timing (we are at about 2100 feet) adjusted the idle but the air/fuel screws still need to be turned all the way down BUT I did get a huge improvement in two areas. No more black smoke except a small puff when I stand on it and a VERY noticeable increase in power across the board. It runs like a top but I know now that I am over-carbed. I wish Edlebrock still made the Rochchester (sp?) like carb. I want very small primaries. Anyway, 600 or 650 is my plan in the future.

All I did was put a $40 dollar Mr. gasket fuel pressure restrictor in line set at 5.5 but I wonder if I turned the fuel delivery down some if it would bring the idle/air screws into play. Eddlebrock says to go 6.5, it doesn't need it. I do not believe I am flooding the carb anymore and since it is running strong and the temp is dead steady maybe I should leave it alone. I don't know. But there has been improvement.

When I ran my dual quad I used a Mr. G regulator set at 3.5 psi which was minimum. Fuel pressure ran a little higher at 4.5.
Don't worry about running out of fuel at that pressure. Mine was good with 2 carbs right to 5500 rpm and 120 mph.
The key to getting your mix screws responsive is in closing the throttle down to cover the transition slot. Might be hard to do on your carb.
With increased initial you'll likely need to limit your mechanical and vac advance.
Good to see (hear) you got it crankin'!!

You might want to verify your timing tab/balancer to see if your 22 degrees is accurate.
http://www.crankshaftcoalition.com/w...op_dead_center

[ubtripn]

Will do, it seemed wrong to me too. The timing mark went to above the reader a little. Had to turn the disti almost hard over counter-clockwise but its performing the best it ever has.

[snj8198]

I wish Edlebrock still made the Rochchester (sp?) like carb. I want very small primaries.

Check out Edelbrock's 650AVS off road carb model # 1826. Technically it is not a spread bore carb but the primaries are smaller than the secondaries which will help pick up air/fuel velocity and may gain you another inch of vacuum. Plus the over all size is better suited for your motor needs. I'm running the exact model on my 489 for now.

[ubtripn]

Thank you I will.