I know this has been covered before here, and on other sites... But, I haven't really found the answer I want. I have a Lazer 25/60 with 86 hours (homeowner), and this will be the 3rd year I run it. Obviously, I want this machine to last a long time, and am wondering should I make the switch to a full synthetic or semi-syn. I change the oil now twice a season, and cost is really not an issue, due to the low quantity needed. It is a Kohler 25hp, and currently I use 10W30 non-synthetic. If yes then what weight/brand of syn? I realize this would be a better suited question for Kohler, but their website did not have a forum like this. Thanks.