Any way you can post a pic of this unit ? Sounds a little much with the silly-con. Honestly if I need to use a sealer I like windsheild butale. Small amounts and you can almost break your parts before the sealer.
A TEST......... With gloves, take that brown muk and put in a flat dish. Let dry, then add to a small plant(potted plant as in isolated). In a week or so or month, see if the plants alive or not. If dead, then i'd say its safe to say that its most likely toxic! If to plants then definitely to us.
* Of course take care of the plant as normal!
As far as the pump idea, unless you produce more then 5 lpm and can pressurize and intend on not using gas, you wont have a need for pumping to the intake. Seriously. Vacuum alone will do all you need. Just matters where you insert the feed. The size line, vacuum source area, and NO vacuum leaks are important. Most carburetors, throttle bodys have ported vacuum outlets for various things; vacuum advance, dashpots, servos, solenoids, ehr (exhaust heat riser), ETC. . So you can do what most do and tap into a large vacuum line with a tee or tap into a ported smaller line that is only operational as you apply the accelerator such as the advance to the distributor.
Its done right or its not done !
Hail HHO.