Rebuilt my Carter BBD on the 318

[mgm1986]

My '68 Fury w/318 started having rough idle issues about a month or so ago. It had a leak in the front of the intake manifold and a vacuum leak in the carburetor gasket. I got the intake manifold gasket replaced and finally yesterday got the carb back on the car after rebuilding it with a kit from Carbs Unlimited. Also had to replace the float which was half full of gas.

So I foolishly put it all back together and realized I never checked the float level. :sSig_noob:

I decided to bolt it up and give it a go anyway, maybe I would luck out. So with a little tinkering of the idle air adj screws and realizing I needed to prime the carb, she fired up and ran. Adjusted the fast idle and regular idle down, and it runs much better all around. I need to check timing and set the idle air adjustment with my timing light and vacuum gauge now that the vacuum leaks are corrected.

As it sits now I notice a very slight delay from the time I step on the gas to the time the engine responds. Maybe half a second pause and it does this at idle and while moving. Doing some research it sounds like this might be due to the float sitting to low and not having enough gas at the ready when I mash the pedal. It doesn't stumble or hesitate just a half second delay from stomp to romp.

If after I adjust the timing, air/fuel and idle and it still does this, is it time to check the float or is there something less obvious that could be causing this?

 

[commando1]

Accelerator pump always rotted out on mine on the cars that had them.

http://board.moparts.org/ubbthreads/showflat.php?Number=5174163

 

[tbm3fan]

Float level. Been there, done that. The BBD has that smaller compartment inside the fuel bowl which houses the accelerator pump. It fills from the top and if the float is too low it won't fill up. Ran into that on mine at every stop. Once I adjusted the float higher I got rid of that. Still other issues so I got rid of the BBD.

 

[mgm1986]

Accelerator pump always rotted out on mine on the cars that had them.

http://board.moparts.org/ubbthreads/showflat.php?Number=5174163

Mine looks to have a different setup, still worth checking I just need to try and understand the directions that came with the rebuild kit. The kit included a new plunger which was replaced.

Some pics of my carb, of course none with the plunger in place.

Here is the top where the plunger sticks out:



This is with the plunger and spring removed.



All apart:

 

[mgm1986]

Float level. Been there, done that. The BBD has that smaller compartment inside the fuel bowl which houses the accelerator pump. It fills from the top and if the float is too low it won't fill up. Ran into that on mine at every stop. Once I adjusted the float higher I got rid of that. Still other issues so I got rid of the BBD.

Great to know from experience it could be that simple. I am hoping to keep the BBD for the rest of the year until I take her off the road this winter for resto at which time I hope to drop in a 340, which is a completely different topic for my other thread!

 

[tbm3fan]

Dead center is the space for the accelerator pump and gas. That small cut out at 7 o/c is where fuel enters. So if the float is low then so is the fuel and if it barely reaches you fill hardly fill it. With a low level you will have to play with the throttle till the car gets going and the basic fuel circuit takes over. Outside of that the engine will seem to run fine except moving from 0 mph.

 

[mgm1986]

Dead center is the space for the accelerator pump and gas. That small cut out at 7 o/c is where fuel enters. So if the float is low then so is the fuel and if it barely reaches you fill hardly fill it. With a low level you will have to play with the throttle till the car gets going and the basic fuel circuit takes over. Outside of that the engine will seem to run fine except moving from 0 mph.

This makes perfect sense, thank you for explaining it clearly!

I went ahead and set the timing and adjusted idle air mixture using a vacuum gauge and it is running much better after that. I still plan to pull the carb and set the float though, just not this weekend cause it will be nice and I want to drive her a bit!