These E3 plugs are great for older riding mowers that are oil-lubed.  Worked wonders on my old Sears Craftsman riding mower.

Put one in my string trimmers and got similar results and got one for my Husqvarna saw, which used to be hard to start.  It starting running like a champ... for a while.  Cut a few trees down, not a lot of usage, then it died.  As, in completely DIED.

Took it to the local Husqvarna dealership service department.  The tech told me, then showed me that my Husqvarna saw is now toast.  The cylinder is burned out inside.  As in the coating on the inside of the piston wall is GONE.  Now, the only thing I can conclude from that, as others have posted online, is that this plug IS NOT SAFE TO USE ON CHAINSAWS and 2 Cycle air-cooled engines of any kind.  I cant prove this beyond a shadow of a doubt, but the tech thought it as the E3 plug and he recommended only the manufacturer's plug for Husky saws.

So, in my opinion these plugs should be have a warning label on them.
These E3 plugs are great for older riding mowers that are oil-lubed. Worked wonders on my old Sears Craftsman riding mower. Put one in my string trimmers and got similar results and got one for my Husqvarna saw, which used to be hard to start. It starting running like a champ... for a while. Cut a few trees down, not a lot of usage, then it died. As, in completely DIED. Took it to the local Husqvarna dealership service department. The tech told me, then showed me that my Husqvarna saw is now toast. The cylinder is burned out inside. As in the coating on the inside of the piston wall is GONE. Now, the only thing I can conclude from that, as others have posted online, is that this plug IS NOT SAFE TO USE ON CHAINSAWS and 2 Cycle air-cooled engines of any kind. I cant prove this beyond a shadow of a doubt, but the tech thought it as the E3 plug and he recommended only the manufacturer's plug for Husky saws. So, in my opinion these plugs should be have a warning label on them.