Go to Burnt Latke's site (you can just google "burnt latke"). It has very good instructions on making a metering device. I suppose engine starter could work, but you couldn't meter it very well, and I doubt it would have as much power as metered propane or MAPP.

Thanks a bunch man ill check that ...

You need to actually measure the right ammount of propane. 4.03% of chamber volume is the target ratio to use. It is picky and needs to be fairly accurate, so your 10% success rate sounds about right for guess work.

O damn lol, oops, i have seen those funky meters before, how do I go about making ...

Allright so I live in wisconsin and right now its about 30 degrese. I was just outside dryfireing my gun with a few different propellents so i could find sometihing better for my gun than gumout, becasue I have a PVC launcher, 3 inch diameter chamber thats 2 feet long, and 2 inch diameter barrel ...