DanOldsMan

Had the Q-Jet rebuilt for my 66 Olds Toro 425 C.U. @ A shop here called "Carbs Only", here are before and after PIC’s curious how the secondaries kick in, It does’nt seem to have kick *** throttle for 385 hp 425 c.u. Big Block;
I have idle set and I am getting 15 lb's per sq inch of vacuum (late timing I assume?) Ithrottle it a little goes up to 20 lb's per sq inch of vacuum( I assume good). Still not sure what else to adjust for the secondaries to kick in. Pic's of vacuum readings to come soon. I am getting my readings from the intake manifold directly.

FIRST BEFORE PIC's



PIC'S AFTER REBUILD






Spring on '66 Q-Jet

Fun71

Assuming the secondary metering rods are correct, you may need to adjust the air door tension.

There is a small slotted head screw on the side of the secondary throttle shaft. It has an Allen set screw on the underside.
Turning this screw increases or decreases the spring tension on the secondary air valve.
Make note of where the slot is pointed since as little as 1/8 turn can make a huge difference in operation.
Hold the slotted screw in place with a screwdriver and slightly loosen the Allen set screw.
Turn the slotted screw a small amount (1/8 turn or less) and re-tighten the Allen set screw.
Drive and verify secondary operation is a smooth transition with no bogging.
Repeat as necessary.




P.S. I like that vacuum hose attached to the rear carb mounting stud.

allyolds68

This:



made all the difference in the way my Q-Jet performed. I had the opposite problem of a bog. My secondaries weren't opening quickly enough

DanOldsMan

My Olds is one owner (in the family, so to speak) and unless the dealer changed the metering rods they are what came with the car in 1966. Yes the vacuum hose attached to the rear carb mounting stud .
Thanks, I will follow the procedure you've given me and post my results.Here is where mine is currently set, so just try back and forth adjustments until the secondaries will kick in. I'll give it a go,

mike8162

There is also a lockout that will not allow the secondaries to open while the choke is on. I'm guessing that it is fully heated up though.

Fun71

That's a good point about the lockout. If it is bent or sticking it could prevent the secondaries from opening even if the choke is fully heated up. This is assuming it's the style mounted on the air horn. I really don't know about a '66 carb.

BILL DEMMER

'66 used a lockout lever on the secondary air valves. i've seen a lot of carbs. where the choke spring had lost some of it's travel and didn't open fully when hot.


bill