Here I go again....if notonething it is another...

239 idles great but now bogs down when I accelerate....fuel consumption is through the roof....needs full choke to get up to speed.

When I close the idle jets the RPM increases...changed power valves and the problem is still the same.

 

Maybe check your spark plug wires. I had changed my plugs, but I had 2 mixed up. Ran really good idle but trying to get up to speed was worthless, just a thought.

 

Is your float level set at specs? Sounds like fuel starvation and needs the choke for the boost. When you move the throttle arm can you see a shot of gas squirting down the carb throat?

Also could be plugged fuel lines anywhere from the tank to the carb will cause a lean condition requiring full choke to get up to speed (and excessive consumption).

If these are OK is your timing set right? Vac advance working on the dizzy and is the vac line connected to the carb?

On your previous question, it had to be the ignition resistor that fixed the problem. These flatty's will run with more than three plugs not firing.

Related to that - are those three plugs still not firing? You could be having trouble with 'bleed-over' from adjacent firing plugs. I covered some of my plug wires with plastic loom that I had trouble with. Typical cross fires will occur in the 1,2 leads on the passenger side and the 6,8 leads on the driver side.

I had a carb that I just couldn't make my truck run with. Changed it for one I picked up at a swap meet and it's like a different truck. Runs like a top and never hesitates. Good luck - hang in there and keep trying - you'll get it eventually and learn a bunch in the process.

 

tim,

Thanks for your info...timing is 2dgs BTDC anI can see the fuel when the throttle is advanced....

I replaced all the plugs, points, rotor, cap, wires and coil and all the ignition components have been checked out and are up to specs....

What has me confused is I rebult the original carb and had the problem so I bought a rebuilt and still had the problem despite getting the electroniuc sideup to speed...

 

plugs are fouling too

 

Let's see.......it's likely you're working on more than one problem here so let's eliminate the possibilities.......starting with the plugs. Are they all fouled? This would indicate too much fuel - typical of running with the choke closed. Is the fouling dark/oily, dark fluffy/dry, or other?

If only the 3 are fouled, problem is most likely between dist and plug. Even new wires can bleed/crossfire. Make sure they're insulated from each other and not resting on the heads. Do you have good spark at these three? Which three are misfiring?

Have you been into the engine? - heads or intake off? Any idea on compression?
More later..........

 

all plugs are dark/oily...all have spark....

she idles great and will accelerate nicely wth a little pressure on the gas peddel...as son as I give more gas she bogs at all speeds....have to use a very very light foot...

I am guessing the ballast resistor and power valve

 

had the same problem on my 239 fouling plugs also . the guy i got the truck from rebuilt the 239 but did not run it. had no power ;backfire ; fouling plugs; .set valve timing ,new carb same old problem pulled intake found intake gasket was leaking . gasket was for 272 new 239 gasket runs great good luck 64bird

 

First, I've never worked on a 239, but here goes anyway. (If you sit around and be quiet people may think you're stupid. If you speak up, they may know it.)
It sounds like you're idling too rich. I use the instructions from my B&S lawn mower engine. Increase the idle mixture until the RPM start to drop, then decrease it slightly. Too lean and you won't come off idle smoothly (backfire up through the carb). The idle circuit is out of the picture once the throttle opens, so if you're too rich then, your jets are too big. I doubt this is the problem. It is possible you're running too lean, but that wouldn't explain the fouled plugs unless the amount of time you've spent working on this problem with it idling is more than the time you've had it out on the road. Vacuum leaks will make it run lean, so check for them by carefully spraying carb cleaner around all the gaskets. Again, based on your fouled plugs, I don't think this is the problem.
Check your distributor for vacuum advance with a timing light and running up the RPM. Also check your distributor mechanical advance by disconnecting the vacuum line and running the RPM up. The timing should advance, but not as much. Lack of advance will rob power, cause poor combustion and I guess could foul plugs. Maybe someone out there knows if it does.
Good Luck,
Johann