I put it into gear and it dies.

I might not have been clear. Set the light to zero and read the timing from the cover. 12 degrees is fine. Make sure the vac adv. is un hooked when you time it. Do you have a light you can borrow just to check against yours? If it won't run at 12 degrees you need to keep digging. When you say it won't run at less than 25 deg. is it dying because it's just idling to slow or can you turn the idle screw up to make it run?
I can turn the idle screw up and it'll run but it runs terrible. sounds like a vw. and none of my friends have a timing light to even check mine against. that's why I had to buy one. even O'Reilly's stopped renting them because nobody uses them anymore