Working on an Echo GT-2000 string trimmer. Rebuilt the carb last season and it was running good then. Now it won't fire. Tried a new plug and tried a small amount of fuel straight into the throat of the carb. Compression is 125 psi. Also regapped the coil to 0.07 inch. The spark will jump a 0.25 inch gap, but very weak and yellow compared to my Stihl trimmer. I'm inclined to replace the coil but not sure if the cost is worth it because I don't know what a new, equal trimmer would cost. The 2000 must be an older model. What would you do?