Vacuum advance?

[txtj79]

How can I check to see if my vacuum advance is working?  I have a 1980 C-10 witha 350 and a Q-jet.

Thanks,

T.J.

[VileZambonie]

Remove the vacuum hose and reinstall it on a manifold vacuum port. You'll hear a change in engine speed and idle quality. Or use a timing light.

[Lt.Del]

Do you have any problems under heavy acceleration?

You can always suck on the vacuum line going to the distr. vac adv. diaphram.  Suck in on it and then put your thumb over the vacuum line.  Release thumb and see if the advance goes back down.  That way you see if your diaphram works ok.

You can manually move the advance under the distr. cap...then put your thumb over ov the hole for the diaphram.  Let your thumb go and see if the advance goes back to normal on the dist. ---that way you can see if diaphram works ok without a tear in it.