hello all,
? ? ? I have a problem with my carburetor.... I assume it's the original carb. I have a 1950 Plymouth w/ the single barrel carter carb in it. I just rebuilt it myself(keep in mind that it's the first one i ever rebuilt) and it sounds pretty good at idle but when you accelerate from a stop it hesitates then seems to catch and goes somewhat smoooth.,.also hesitates at a cruise and if you punch it the slightest bit it does the same.i tried to do some adjusting but it always does the same. Then i noticed that when warmed up that gas drips out from where the throttle linkage connects to the acc pump. any ideas or suggestions??I would love some help if anyone has any!!!
Number one, the hesitation is most likely not enough of a rich mixture on acceleration. That's the job of the acc. pump. It allows you to enrichen the mixture for a quick start,by pumping the gas pedal a couple of times before cranking, and it also shoots a squirt of raw gas down the carb throat to stop the engine going 'lean' when you 'hit the gas' to pick up speed. If the engine 'sags' when you open her up, then the acc. pump needs to be moved up a notch to make the pump stroke longer when you push on the gas pedal. The longer the stroke in relation to gas pedal movement, the more gas injected into the carb throat. There are holes in the bell crank to adjust this. Sometimes you have to bend,or unbend, the linkages to achieve this. The links may have been bent over the years from heavy footers slamming their foot down on the gas pedal doing jack rabbit starts.
? ?Number two,there is a sleeve gasket around the pump piston and I suspect that or something nearby is what's leaking on your carb. It's common and you just need to pay more attention to the acc. pump rebuild. The pump is immersed in the gasoline on one side of the carb float chamber and drops down to the float floor to pump a small squirt of gas through a tube drilled in the carb body that ends in the carb throat. When you have the carb on your bench, fill it with water with a little food dye and troubleshoot it that way,much easier. Just remember to get all the water out before you put it back on the car. Any small droplets of water that are overlooked will make it stumble for a while until they are injested or percolated out by engine heat. Good luck.? ?
I agree, and I think that it is as simple as the accel pump is not right. I think it is torn, or snagged, in it's bore.
Start the car and run it for a few seconds to fill the carb with gas. Then shut it off, and remove the air cleaner. Look down the carb throat and work the throttle linkage to full open fairly fast. If you see a stream of gas squirt into the carb, the pump is working. If not, there's your trouble.
If there is a stream of gas, and the car isn't running right, it may be WAAAAAYY lean on the mix screw.
My dear, Plymouths, I hope the passenger compartment floor makes the stop for heavy footer?s gas pedal, and not a small lever in the carb....
Greetings! Go
Sometimes, especially with an old NOS rebuild kit, that accelerator pump piston can get dried out. I've had that happen to me twice and both times it corrected itself within a week or two. I assume it softened up once it sat in the gas for a while.
There is also a secondary enrichment device within the carb that is controlled by vacuum from the intake manifold, or actually the lack there of. This is the little spring and rod deal opposite the acc pump. Its job is to complete the enrichment of the mix when the pump has shot its bolt so to speak. There is a vacuum slot cut into the carb to gasket to feed this port on the carb. At high vacuum at idle pulls the metering rod down against a spring. When the intake looses vacuum under acceleration, the spring moves the needle up and out of the jet allowing more fuel in the mix, as vacuum is restored the needle is pulld back into the jet cutting this flow. If your acc pump is working and this circuit is not your initial acceleration will bog down till the main jet can make up the difffernce. It issentiall that the carb gasket have the slots that line up with the holls on the base of the carb. Make sure this is so and that the the assembly moves up and down easily agains the pressure of the spring. The needle should be up at rest with no vacuum present but should move down into the jet with no resistance other than the spring.
All previous advice is very much to the point, but the fix may be as simple as removing the soft plug just below the lid (not the one under the bowl) and running a welding tip cleaner or fine wire through the jet which may be partially blocked from dirt which was dislodged during the original rebuild. A few strokes of the throttle should flush this out before reinserting the plug. I have found that a small set of "diagonal" wire cutters are useful in removing the plug.