[135SoHc]

1979 B200 5.2 with its matching original carter BBD. This has been a problem for awhile now and I am almost out of ideas. At idle the venturi's are discharging fuel like nothing else, its dribbling out and flooding the throttle plate enough that the engine runs rough and fuel economy has been reduced by a noticeable amount.


The carburetor has been gone through multiple times and everything is adjusted to spec. The vacuum step up piston/metering rods are working as best they can. The assembly draws down when the engine runs and if you lift it up manually it starts to go richer like it should. The two main jets have been replaced with new ones of the same stock size (.086") and as of right now the float is actually set lower than the stock setting because the fuel bowl was overfilling and soaking out through the gasket. It still exhibits the same problem but nowhere nearly as bad.

The only thing left to replace would be the float as it does have the original float which externally appears to be in good functional condition. The next step for this thing is the trash can.

 

[135SoHc]

This van only has the regular two port in-out inline type filter under the floor board near the charcoal cannister. I have replaced it a few times already along with the needle/seat assembly since they are included in the kits. This one has the brass tank type float, dad swears its the original one. I would have thought by 79 it had the black plastic version.

Something I did observe though. When I had the air-horn portion of the carb removed to check the fuel level and cranked the motor over (spark disabled) the spurt of fuel into the carb from the feed line seemed rather violent. Granted it would normally never be seen since its all down inside the body and under the air-horn but I was surprised to see it that strong. I was expecting more of a steady trickle. Fuel pump was replaced in 2004, just a stock airtex unit from the parts store.

 

[135SoHc]

Some major developments since the last time I posted. I did order and replace the float, even set lower than it should have been it was still pissing gas at idle. No more for me.

The 'fix' >>http://www.amazon.com/Edelbrock-1801-Thunder-Series-Carburetor/dp/B000VDLQB8 Picked up a second hand 4bbl intake manifold from ebay. The rest of the supporting parts are on their way as well. The end of an era and the beginning of a new one for the B van starts next month

 

[135SoHc]

I wonder if the needle is missing from the carb, or installed backwards on the seat.

Did you measure the fuel pressure? For carbs, should be about 7 psi.

The needle is there. On the 'test stand' (old intake manifold) with just gravity forcing the fuel down it functioned like it was supposed to. pressure was 5.5 steady.

I hope your new setup solves the issue. Did you ever explore the possibility that the return line to the tank is restricted?

If it had a return. This van doesnt have the 3 port fuel filter. Its got a supply and vent line to/from the tank.


Just for fun I borrowed the holley 2280 from my parts wagon (85 B250) and it ran perfectly. I seriously did absolutely nothing other than install it as-removed from another 318 with even more miles on it.