1987 318 Tuning with Summit Carb

sarguy01 said

Yep, it was me trying to figure out a carb's tuning when a weak ignition was the problem. It did not like 6 degrees. Now that the ignition is good, I have the timing set back up at 12. I have a limiter plate in the dizzy set to 18 max, so I might bump the timing up to 14 and see how it reacts. I also recurved the Proform dizzy as it came with a lightning fast curve. Still might need to fine tune the curve.

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The base rule... Timing FIRST!

Timing will almost always has an effect on carb setting, carb setting don't usually control timing with an idle tune up. Foundation, idle tune sets the plate for everything that stacks on top of it. As with a house, poor foundation, nothing you build on top will be optimized. JMOP, stop messing with the IFR, air bleeds until you have a stable base timing level. Reset the carb back to a baseline and start over.

If the idle timing drops when RPM is lower, the mechanical is bleeding in, Advance the distributor and turn the rpm back down until the timing is stable in park and in gear. That engine should idle smoothly at 750-800 rpm with out issue and maybe drop 50-100 in gear when it is right. You will NOT get a good tune up with the timing moving like that. The base timing should not move at all.

Yes, systems have to be functioning properly to get things running properly. That cam/engine/carb set up should be a very simple tune up. If the mix screws don't do anything to the idle speed/vac readings, you have other issues like a vac leak, dripping fuel somewhere