1948 F2 vacuum advance question
 

1948 F2, 226 engine
When I check the function of the vacuum advance, do I just check that it works or should it hold a vacuum? If it should hold a vacuum, how much?
I don't recall seeing this info in the book that came with my vacuum pump/gauge setup.
Thank you
MarkG

I have a rebuilt carb coming. It had been on the shelf for a while so might need a little lube. I will see if this help get rid of the dead spot when taking off from a stop.

Re: 1948 F2 vacuum advance question
 

You would apply vacuum and see movement.
No movement is bad. With steady vacuum source,
it should not leak down.
Dead spot taking off that is always there (even on
a warm engine) is probably the accelerator pump
circuit. The 94 on my flathead had a ton of dirt and
crap in all the channels of the booster, where gas
is supposed to come out. Once cleaned out and I
was getting a "shot" of gas out of the booster,
I had no dead spot.

Re: 1948 F2 vacuum advance question
 

If you use a MityVac hand pump it is easier to test for a leaky can. It should hold vacuum and you should see movement.

Always check the wire under the distributor plate for bare wire grounding out. I had a really vexing problem with one that stumbled horribly just off idle, and sometimes backfired. Turned out one of the screws holding the points to the plate stuck thru the plate more than usual, and would contact that wire each time the vacuum advanced or retarded.

Re: 1948 F2 vacuum advance question
 

OK! :) Not just a stumble; I let it warm up some in the morning and when the gas pedal is pressed down to take off, it dies. I did check, there is a stream of gas being shot out when the accelerator pump is activated.
I will check the vacuum advance. I should have the carb tomorrow. I will blow out any cob webs, install it and see where I set.

Re: 1948 F2 vacuum advance question
 

Checked the advance, looks to be working ok. While I had the vacuum gauge I decided to check manifold vacuum. Poor baby needs a valve job. Steady needle bounce at idle and up. This could be why the popping when letting off the gas when going down hill. Hate to pull the head and find it's more then a grind job, this is my only transport even my Model T is down getting new babbitt in the mains.