So i have a auger that i bought new last season and added mobil 1 5w-30 (5w-30 is what manual called for). for the first fill. i used the auger for a total run time of probably an hour this year. i want to use a synthetic 5w-30 i will probably run it 2-5 hours per year. how long can i go before a change is needed? what brad has the best pumpiblilty at low temps? and should i just fill the oil up until i can see it in the dank case because it docent say how much it takes.