engine running rough, backfiring, no power

[1v35bonanza]

in my 1976 124 after successfully installing a new gear reduction starter, the car started normally, idled normally and as i took off for a ride it ran normally for about 5-10 minutes and then it just started running rough with no power and backfired. i had to pump the gas pedal to keep it going and that didn't work very well. i ended up shuting it down and towing it home. i am wondering if somehow we messed up something taking the old starter out through the top of the engine compartment. one wire was off but we reconnected it to the bottom of the carb.area. i'm confused because the engine ran fine at start up and for 5-10 minutes on the road. i've had no previous problems like this with the car, in fact, it is a smooth running machine. any ideas?

[djape1977]

check the timing

[Boris61]

Had the exact same symptoms and it was a bad distributed cap. You might check this.