well you would have to get it hot then when it dies on ya be quick and check the spark. but you can count on one thing if a lot of people tell ya its the coil it gona be the coil. and i am telling ya also its the coil. big problem for the 80's/85's great line trimmers dont get me wrong, the BEST their ever was but weak in the coil.
opps i loked at you thread again. and you did not mention the model# but if its a 4-mix they also have problems with the coil as well.