I have a rebuilt (by PO) 1.7L motor in my '71 that was just started for the first time. It has been converted to a single Weber 32/36 carb (I know, not the best setup). It sounded odd, like a Harley but I was just thrilled it ran. When it wouldn't idle I decided to check if all cylinders were running. #2 and #4 aren't running since removing the plug wires made no difference in running. I didn't think to feel for warm exhaust pipes but I'm pretty certain they're not running. THere is spark at #2 and #4 plugs and I'm quite certain I have the wires in correct locations on distributor. I tried moving them around but the only combination that runs is where #1 and #3 are supposed to be. The timing is set at 34 deg. BTDC (as it should be for carb) and when I set the valve clearances, the cylinders all reached TDC on compression stroke when they should relative to where the rotor was pointing .
Was the engine built incorrectly?
Are the intake runers for #2 and #4 blocked by the wrong gasket under the carb?
Are my ignition wires in the wrong order?
What have I missed?