Check out this thread on "The Ford Barn" : https://www.fordbarn.com/forum/showthread.php?t=261218&highlight=fire
If it's a 6 volt one, make sure your generator is working. It'll start off of the battery, but under load it needs at least 6.5 volts to operate. Also make sure you use the plug wires they suggest.
There have been threads on it here and on the Fordbarn. For every one negative review, there are 3 who chime in with positive reviews and experiences. Full voltage and installing exactly as the instructions dictate seem to be the keys.