Carb. popping

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blmopar1

blmopar1

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When I accel normally I get a slight hesitation ,but when I try hittting the gas hard from a start it pops hard and stalls.I set the timing at TDC and adjusted the carb fuel mix screws but it doesnt help.Thanks for any help
 
What is your initial timing set at? I had the same problem after building my engine. Once I bumped up the initial timing around 18* no popping.
 
What kind of carb are you running and did this problem just crop up. Also pull off the distributor cap and with a socket and handle on the end of the crank turn the engine till you see the dizzy rotor move. Then turn the engine in the opposite direction and tell us how far it turned back before the rotor moved. You're looking for a stretched timing chain or it jumped a tooth.

Terry
 
blmopar1 said:
When I accel normally I get a slight hesitation ,but when I try hittting the gas hard from a start it pops hard and stalls.I set the timing at TDC and adjusted the carb fuel mix screws but it doesnt help.Thanks for any help
Click to expand...

The accelerator pump is probably bad, and it needs more initial timing.

With the engine off, look in the carb while you pump the throttle. Gas should be shooting in. If not or just a trickle, it needs some carb work.
 
The accelorator pump is spraying ok.The carb is a 700 dbl pump which is from an older 340 race motor with larger than stock jets (70 jets-stock 67 jets).It also has the stock points dist.I set the timing by disconnecting the vac advance and set it at TDC (acording to the book).Is this the wrong way to set it.If I check the dwell it is at 21 when it should be at 30.Thanks
 
blmopar1 said:
The accelorator pump is spraying ok.The carb is a 700 dbl pump which is from an older 340 race motor with larger than stock jets (70 jets-stock 67 jets).It also has the stock points dist.I set the timing by disconnecting the vac advance and set it at TDC (acording to the book).Is this the wrong way to set it.If I check the dwell it is at 21 when it should be at 30.Thanks
Click to expand...

Crank the motor up and do what redhot said. You've got to have initial timing. You if don't have any means of seeing the 33 degrees at 3000 RPM on the balancer then just make sure you have 16 degrees (give or take) while the motor is idling with the advance unhooked and plugged off. This should get you running much better.
 
TDC won't work. The book says that mostly for emissions back then. A good starting point is 8* BTDC with a stock distributor so you will have about 33* total. Then adjust points to 28-32*, then lastly adjust the carb.
 
Setting timing using the total method might get it to run, BUT, it won't be the best set up for your engine unless you get lucky and all the stars and planets align.

initial, total, curve, vac adv.
 
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