When i start up the van it pops through the exhaust and carb,the timing seems right but ive found this servo pipe which has perished and has a half inch split in it ,would this cause the misfire and popping through exhaust also ticks over but when revved it pops
will also cause a running imbalance as the air leak on the left side causes the left side cylinders to run a little lean, you compensate by adjusting the idle screw on the carb to get CO correct but then it's all too rich and the HC goes up, failing MOT; the steel mesh reinforced hose rusts from the inside and fails/leaks
Ive removed rotton pipe and blanked it off for now just to try it and runs pretty good now and tappets have stopped rattling ,only thing i found was if i put my foot on accelerator quick its got a bit of a flat spot.also what is this should it be connected to anything.
The is/was a reducing T piece in the fuel line from the tank to feed the pump, might be capped or just removed. Best to check in case you have a potential leak point.