if you want the basic spec's for each component impco has a product brochure with these on thier website
ht tp://w w w.impcotechnologies.com/IMPCO-catalogs.asp

just remove the spaces i added in the url and that page has 2 links, one is for low resolution pdf file and the 2nd link is hi resolution. Just find the page your component is on and there is spec's and diagrams and Impco part numbers.
Unfortunately there are no troubleshooting sections that i can find at the moment but the pressure spec's may be of some help for you to determine which component may be failing or maladjusted.
when i get more time i will look further and see if i can find anything more specific to troubleshooting.

BUT... based on your description of the issue your having it sounds to me like either the vaporizer is overpressuring the mixer OR the mixer may have a bad diaphram or is just out of adjustment.