Minor Engine Issues - Help Please

[Long Island RT]

I have stroked 440 with a Proform 950 carb and a 600" lift Hughes flat tappet hydraulic cam.  The car is also a manual.

Problem 1: When I push the clutch in after cruising - The engine does not want to return back to idle unless I force it (by grabbing it with the clutch in gear, then it will stay @ idle).  My double return spring is fully functional and the linkage has plenty of tension to return the throttle.  it stays around 2000 rpm unless I "force" it lower.

Problem 2:  After a cruise, and I shut the engine off - I get run-on.  The engine runs for a few seconds and then "poofs" to a stop.  Very embarrassing.  It only happens when the engine is warm.  I have 36° total advance but I can't seem to get a good reading @ idle (maybe because of the MSD?).  The engine only has about 200 miles on it and this just started happening.

Any insight would be appreciated.
Thanks

[elacruze]

This is a symptom typical of having your initial timing advance too low and your advance curve too soon. When you 'force' the idle lower, what you're doing is 'forcing' the RPM low enough for the mechanical advance to retard, then the lower idle timing keeps the engine running slower.

Set your base timing to best idle vacuum. Reset your idle speed and mixture screws as necessary. You'll probably find that you have to back the speed screw out considerably with additional timing, and may have to lean the idle mixture as well.

Let us know more about your present condition, current timing spec, compression, etc.

[Long Island RT]

I can't seem to get a decent read on timing at idle - the mark is jumping all over the place.  I have one of those "set the advance on the gun" timing lights.  I thought I remember something about them not working properly with an MSD.
My compression is 10.9:1.
Eddy heads prepped by Hughes Engines and matched to an Indy Dual Plane intake.
Pro-Comp mechanical advance distributor.
Firecore wires.
MSD 6AL
MSD Blaster II coil.
NGK 4291 ZFR6F-11 spark plugs

I'll give the idle adjust to vacuum a shot in the next few days and go from there.

How about the engine run-on? - Is that related?

Thanks

[firefighter3931]

Good advice from Elacruze as usual 

MSD boxes won't be compatible with a dialback timing light....get one without the dialback feature. You could have an issue with the throttle blades catching on the carb base gasket so check that....i've seen that before. 

Have a look at the float level...if the floats are set too high it could be dumping raw fuel into the intake manifold causing run on. The fuel level should be even with the bottom of the sight glass.



Ron