Correction: Not a Go Cart, My Wheels Are 28 inch, Not 18 Inch.

John

 

AZ520,

The stock setup for the 1406 is .098 primary jets and .075/.047 rods.

Relative to stock, .095 jets and .075/.047 rods would be 15% leaner on the first rod step and 8% leaner on the second step (WOT). This makes sense since this setup has smaller jets.

For your current setup, relative to stock, .095 jets and .067/.055 rods would be 14% richer on the first step and 19% leaner on the second step (WOT). A rather odd combination due to the rods not having much difference between the first step and second step.

John

 

I now have been running .065x.052, odd indeed, but the plugs, wideband, and seat of pants don't lie.

 

So that is 21% richer on first step, 15% leaner on rich step. Whatever your car likes, "they" say.

For me, I don't have a wideband. Had to go by fuel mileage, plugs, pinging or surging, off idle/part throttle responsiveness.

John

 

Just an update, I picked up a street demon thernoquad 650 cfm to try because the edelbrock was getting to hard to start when hot. The street demon runs much better and way more responsive. I could not tune it perfectly after all types of jetting changes, it goes to rich if you get just get into the secondaries a little bit and I cant tune it out, it aslo hesitates if you stomp on the throttle. the jettting also was reduced:


Street Demon jetting stock oldsmobile 350


76 primary
78 secondary
6052 rods
green spring

Next I am trying to get a quadrajet put together and running, I have rebuilt a stock unit from a 1976, I rebushed the shafts and am waiting on a new pump assy. From what I have been reading if these are set-up correctly they are just about as good as fuel injection. I will find out soon!

 

The "carb problems" might also be ignition related problems (weak coil output, timing, wires,) somewhat.

I would have tuned it by disconnecting the secondary transfer rod, so only the 2 barrels up front were what I was dealing with, and the springs, rods, front jets, and pump shot and shooter. If the spark to the plugs is strong and get a leaness hesitation when you punch it moving the rod to the top hole might help, and if still not enough then changing the shooter to a larger hole size, in the shooters, should give you even more gas to go into the sudden in rush of air.

3 Holes on the pump shot arm and the 625 is usually in the middle, but may need to be moved in the top hole. If still not enough fuel fast enough, then you need the larger shooter hole sizes usually.

 

The demon is the problem, never had those problems with edelbrock, I have tried everything with the demon and its just a common problem. Running just on the primary circuit the demon is perfect. The secondaries pull too much fuel when you first get into them and then not enough when you open it up all the way you have to make a compromise. I have tried everything, jets, air door adustments, pump shot, you name it. I still prefer it over the edelbrock, runs much better all around, but I am after perfection. The quadrajet has metering rods on the secondaries so I think thats going to be perfect.

 

The Qjet should get you there, especially if it is off a 76 Olds 350. You can change your part throttle a lot just by adjusting your APT. Just take note of where you start out. Just two turns of my APT made a 3 mpg difference, a big time seat of the pants and a difference at the the track. Surprised you had the secondary issues with the Street Demon.