87 Civic high idle problem

Trying to sort out a little issue for a friend of mine... '87 Civic,
auto, D13A1 engine with Keihin 2bbl and manual choke... it's recently
started idling too high, and seems to get higher as the car warms up.
She can start it cold without even needing to engage the choke.

I've checked all the cables and linkages, all seem to working properly,
nothing sticking. Idle screw is backed out all the way. Primary
butterfly appears to be fully closed, yet the idle (if you can call it
that) just keeps speeding up.

Only thing I can think of is an internal leak in the carb; there does
seem to be some gas leaking down the outside of the carb on the side
opposite the float bowl as well, and the hat screws were, if not really
loose, then not really down tight... but even then, the butterfly looks
fully closed and it's running as if the thing is halfway open.

 

its getting way too much gas. there must be fuel flooded in it somewhere and
it's trying to burn that and the fuel that's being pumped into at the same
time. try this: get a bottle like a 2 litre pop bottle and disconnect the
fuel line going into the carburator and put the fuel line into the bottle.
start the engine and let it burn the fuel trapped in the carburator out
until the car stalls. if it fills the 2 litre bottle before it stalls out
you'll have to have another bottle handy. once the excess fuel is burned out
reconnect the fuel line and see if it goes back to normal.

-jeff

 

that should bring it back to normal but if there is an internal leak in the
carburator then it may flood itself out again. at which point it will be in
need of another carb or rebuild the one it has.
-jeff