I have a Husqvarna HU 725AWD/BBC with a B&S engine, model 128M02-0134-F1. Bought it new 3 or 4 years ago. Regular maintenance performed. The only fuel ever ran in it is TruFuel 4 cycle ethanol free (grey can). Normal operations it starts the very first pull and will run perfectly until it runs out of fuel. Or you can shut it off and restart it no problems... MOST OF THE TIME. However, over the last few months at random times after you shut it off, wait just a couple of minutes, then attempt a restart, it will not start. Park it, wait till the next day and it starts the first pull. It does not smoke, does not spit, sputter or cough. It runs TIP TOP when it starts. Cold start always on first pull. After you run it, and not every time, very random, wont restart. Please advise.