This my first season with my blower and it has an open chain and I use the spray chain lube that does not fling off.................but now a question about the idler sprocket . The user guide I have and even for other makes that I have researched are very vague about how tight should chain be . Twice now I have loosened the idler bolt, let sprocket drop down to chain (so tighter without forcing it) then I tighten the bolt and spray the chain. But it seems after a few hours the chain seem fairly loose (not touching the idler even at times) What thoughts? I have an AgriEase 50 inch which is a knockoff of the Agritrend.