59A-B Vacuum at dipstick tube

[Ronnieroadster]

Originally Posted by piewagn

No PCV Ronnie....


Intake leak has crossed my mind, but would that give me the vacuum readings I'm getting?

Since your running three deuces I have experienced when tuning three carbs the vacuum gauge needle bouncing similar to what your seeing. But the engine did not have any vacuum in the crankcase issue.

For an engine with no issues here's how I solved the bouncing needle issue. First thing that helped was a slight increase in the idle setting on the center carb. Next setting all three carbs so they pulled the same air at idle using a Unisyn gauge helped as well. And final adjustment adjusting all six idle air mixture screws to where the vacuum reading is the highest.

Another detail when additional air is getting into the intake plenum below the carbs the vacuum reading will go up along with the curb idle. The additional air will cause a lean condition thus some ignition misfiring will take place due to being to lean. Vacuum in the crankcase is causing a lean condition more air below the carbs into the intake runners finding the reason for this additional air will solve most of the problems.
Ronnieroadster