Motorcraft 2100 idle too rich SOLVED!

[Fabulous50s]

Hello all!

Had my 352 running for over an hour now, checking cooling system, oil pressure, leaks, etc.

The idle seems rich as indicated by exhaust smell/color.
This is all with the car still on stands and me blipping the throttle, I have yet to drive it. I started out with both idle screws at 1.5 turns out, and ended up with both of them all the way in. Idle still on the rich side. I eliminated (and capped) the hot air choke in favor of an electric choke, so there is some excess air that isnt there now. If I pull the vacuum line from the brake booster and meter some air into the manifold, the idle is leans out to where it should be.

I rebuilt this carb with a kit from the parts store.

Would the float level have any effect on the idle circuit? I dont think so, but I dont know what other variables there are.

Thanks for the collective wisdom of this site!

[Hoosier Hurricane]

It sounds like the power valve is leaking fuel into the intake.  I know you rebuilt the carb, but it is still possible the diaphragm in the power valve is not sealing or the gasket under the valve is leaking.  The float level has little effect on idle mixture, unless it is so high that the carb floods.  If I remember correctly, the power valve is under a cover on the bottom of the fuel bowl.  Remove the cover, if there is gas in it, the power valve is the problem.  Has the engine backfired?  That can rupture the power valve diaphragm.   John

[Fabulous50s]

No backfires, and no gas under that diaphragm. I pulled the top of the carb to observe the fuel (I have a 5psi electric fuel pump) the fuel stops when the float is dead level. I set the float dry to whatever the kit said to, cant remember it was 3 years ago. The carb was dry until a year ago when I first ran the engine with a gravity fuel tank (quart of oil bottle) about a foot high.

I'll remove the carb and double check that diaphragm.

[Fabulous50s]

SOLVED!

Power valve was replaced during rebuild. I had gas in the lower portion (vacuum side) if the power valve. Bad valve right? Nope. Fuel was leaking by the supplied gasket. There considering my float bowl would be empty after a few hours.

Used this gasket and applied a light coat of Gasoila pipe dope to all sides with rubber gloves. Snugged it down and now fuel stays put!

Hope this may help someone.