Walt , what brand of oil did you buy? I buy my delo 100 on the east side of Austin. They sell in bulk just put in 5 gallon buckets. It's about 70 miles from me but nobody carries it around here.
It is a Texaco brand. The dealer was in Wharton, Texas but they switched to Shell products. It meets the specs suggested by Detroit. I ran the genset for about an hour yesterday and it didn't seem to mind the 40 wt. I am going to run it from now on. It is not one engine that costs a lot to maintain, it is all of them that is kicking my butt.
1 Excursion in the shop for a seal right now
1 Allis Chalmers Tractor in the shop for a clutch right now
1 John Deer Mower
2 boat motors
2 four wheelers, one of which I just adjusted the valves and rebuilt the carb last weekend
1 echo weedeater
4 Stihl chainsaws.
1 Silver Eagle bus
Son of a bisquit eater I am up to my butt in mechanical work. Lets not even get started on batteries. So when I can find deals on bulk stuff like oil I try to get all I can right then and there.