Hi all. Please help. I am working on my lesco backpack blower. It seems to have lost spark but when I pull the plug and check I see spark until the RPMS die down from me pulling the starter rope. When I leave the plug in and I hook up my spark tester to the plug wire I down see any spark due to (guessing) lower RPM due to compression with plug in. Am I missing something? Will coil get weak like this is indicating? If so then how to fix is my next question? thanks in advance for any help.