Corolla motor problem

[82 toyota]

Hi, I'm french and live in Canada so I might not always use the right mechanical terms.
I have a 1982 Corolla DLX from California. The motor wasn't running smoothly. I changed the carburetor with a rebuilt one bought in the states just to find out that the new carburetor cannot function properly. You just couldn'T make any adjustements on it when it was installed. I put back the old one and got it adjusted pretty well with the motor running at 750 RPM. The car was still a little shaky, so I bought a ''advanced timing light '' to get it timed. The car is supposed to be at 7 degrees before TDC. I put the timing light at 7 degrees to have both marks (the one on the driving pulley and the one on the block) lined, BUT there is nothing visible when the timing light is at 7 degrees. I need to put it up to 50 degrees to be able to notice both marks getting somewhat lined (weird). I go for a test drive and when I accelerated the motor just started to overspeed like crazy. There is NOTHING I can do to make it stop. The motor is just racing.

Could the problem be the timing chain jumped a tooth?
This would explain the unadjustable carburetor, motor overspeeding and the timing being WAY off. Changing the timing chain is a very hard job, maybe it can be something else?
P.S. BTW the car has 206000miles

[tron1.8]

Was the vacuum advance still hooked up when you set the timing? It is two vacuum lines that comes from the base of the carb to the dizzy. Also make sure the gas cable/linkage isn't sticking and the spring is hooked up. There are a few people in Canada on 3tcgarage that might be close to you.

[82 toyota]

The vacuum advance is well plugged and the gas cable isn't sticking. I'm pretty sure that it's the timing chain that jumped a notch or two. :s