Hey folks, new to the forum. Thanks in advance. I've got the Troybilt Big Red trimmer with interchangeable attachments. Recently started having trouble. It wil start/idle with relative ease. Half a dozen pulls with the air intake completely closed. Problem is when I open the intake and rev it, it dies. It's 4/5years old and outside of plugs, oil and running Sea Foam thru it every now and again, haven't had it worked on. I'm pretty handy but don't know jack about engines. I'm sure this problem has been addressed dozens of times, but could you point me to some links, details? Thx, SR