WOL time out

using smart phone with "WAKE ON LAN" app. to wake my pc using internet. works great. If pc has been off for more that 1 1/2 minutes WOL won't start pc , must use power button on pc. where is the problem? router or NIC ? Windows 7 home premium / verizon actiontec MI424wr rev I router /
marvel Yukon 88E8050 PCI-E ASF ethernet controler card. I have updated NIC drivers. need help please