Manifold Vacuum Advance what am I not getting?

340inabbody said

Sounds right … Turk is giving me good guidance to visit the balancer checking the advance of the motor.

Ive been reading about making sure the transfer slot is like 1/16 no more at idle. The way I understand this is that if there is too much transfer slot opening it will not allow enough flow to the pilot idle path down the emulsion tube/path. Is that what you’re thinking?

I was going to look at the carb after I got it to a point I can run it. Looks now maybe the initial advance is too high at 42°. I e just had it hammered in my head to give the motor what it wants and was using vacuum as part of the process. When is too much I don’t know. Some have said my motor could want as much as 50°???..??

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Ok, that’s another rule of thumb as far as T slot exposure.

I start with a square slot and then open the throttle to get it to idle.

Once I finalize everything I verify the T slots are not open so far that the mixture screws don’t work.

There is no tuning magic in T slot exposure. They can’t be open so far the mixture screws don’t work but they don’t need to be damn near shut to work properly either.

Edit: if you end up with the throttle blades too far open and mixture screws don’t work, we do t just grab the vacuum hose and hook it to manifold vacuum.

I drill holes in the throttle blades so they shut further and correct T slot exposure.

Resorting to MVA to get one to idle is my last resort.

Because in the end, most time guys end up right where you are. It’s not a fun place for sure.