Running on 2 Cylinders Options

[rickso71]

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?

[rickso71]

Yes, 1-4-3-2 firing order. #1 is not top left on my distributor (different for carbs) but bottom right... trust me. Found the problem. The adapter plate between the carb and the intake runners has two holes, one for each barrel and is meant for a plain old dual carb. With the progressive, only the primary is used normally, so that fed #1 and #3. When the secondary kicks in it feeds #2 and #4. I need a different plate, one with a single hole that covers both barrels.

Ran surprisingly well on 2 cylinders but wouldn't hold an idle below 1000RPM. Going to check with Redline on whether I need a new plate or can just modify existing one.