1987 Honda Civic DX, D15A2 engine

I took off the carb to have it rebuilt. When I put it back on, the idle doesn't drop below 2000 rpm. When I turn off ignition, the car vibrates a lot before going out, just like how it did when I disconnected my brake booster hose once and forgot to reconnect it.

I've checked that all vacuum hoses are connected. I torqued down the carb and use gasoline-safe gasket maker between the carb and mount flange.

Ideas?