Good deal, glad you got it fixed! It makes NO difference at all with respect to the ignition coils what speed the engine is at when you engage or disengage the blades. It can make a difference with an electric clutch or your primary deck belt though what speed engine is at when bladed are engaged, but makes NO difference when blades are disengaged! Typically, I would recommend turning the engine off at idle speed unless you get afterfire (backfire). In that case, you may have to play around with the throttle at different speeds to find a spot where there is minimal or no afterfire. If you just used the moer hard for a long period of time, idle it for a minute or two before shutdown. I personally like to start ALL equipment at the slowest speed possible, especially when the engine is "cold". This is more easily done if you have a seperate choke control. But can be done if choke and throttle are in the same lever... As soon as the engine starts, I bring it to idle or just above to "warm up". You don't get in a vehicle and run it up to 3600 RPM the second it starts, same thing here... Some people will have different views but those are mine.