I've got an examrk that doesn't want to start on cool/cold mornings (40 degrees). It turns over real slow, not fast enough to start. I've changed the battery with a Walmart brand battery and initially it worked, but not it doesn't. I've charged the battery to 13.2 volts and it still doesn't spin fast enough to start. One of my guysthink the problem is the starter, but I have jump started the mower and after it warms up, it will restart normally. Currently I run with 30wt oil, but I think I'll try 10-30 and see if that doesn't help. Any suggestions?