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Old 11-30-2019, 11:11 AM
tortuga tortuga is offline
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Join Date: May 2015
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Default RPM hangs a few hundred high on decelerations?

MSD distributor
Pop the cap and see if your rotor snaps right back CW when the mech advance is simulated br gently twisting it CCW.

No? Mine too.

So bump the motor until the rotor is pointing straight fwd (just a convenient spot I always use)
Mark straight fwd where the rotor is on the top.
Take off the hold down.
I like to put a second mark where the rotor rotates to as the unit is lifted out, this will be about 30 degrees CCW from fwd.
Pull the distributor, stuff a rag in the hole. DONT TURN THE MOTOR.
This is also a good time to inspect your drive gear, if it’s worn you need to replace...
Anyway, now mark and remove the upper plastic housing (two Allen screws inside)
Now you can play with the thing and see where the point is where the upper shaft routes around the lower.
I gave mine a few shots of brake cleaner and viola! Upper snaps right back under spring tension. I thoroughly cleaned the whole mess and finished up with putting some gun oil into the little seam where they rotate independently, working it upside down in an effort to get some oil between the shafts.
Once happy another good solvent free wipe down. I figure a bit of oil coating all the rust prove lower guts can’t hurt.
Put it all back together and watch your R’s drop right to where they should be...

Plus you have somewhere to hide from lingering house guests.

Your mileage may vary but it sure cured this little niggling issue for me...

Steve H
SPF 1764
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Ford Racing 427 SB
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