I own 5 LX188, and one lx279 which often had problems with in hot summer weather. It would run for about an hour then quickly lose power and shut down. It generally would run with full tank, but have problems with lower levels. Then only start with choke. It seemed short of fuel. I installed new fuel pump and filter and then installed a T verticle line in fuel line just in front of steering pedistal and monitors fuel level. With 3/4 tank, it ran good for a while and then the level of fuel would of course drop and you must plug verticle line to prevent sucking of air... anyway.. in all of this, if found that when the mower got hot, I would see some air... vapor bubbles coming up the verticle tube. Thought a cracked pickup line, and installed a new one.... THE PROBLEM?? It appears that any ethonal in the field would quickly boil in hot summer months, especially when it was being sucked up from tank when below half full. Found fuel temperatures at engine to be above 145F.... though I saw 165 at carb where ethonal does boil at 173F... I took off hood and mower runs without failing.....anyway, coils and other issues maybe the problem, but consider if you use ethonal fuel with low vapor pressure