It is a honda 610 twin 18 HP.TWIN hooked to a 10 KW gen ....Propane...10 years oid with PENSOIL 30wt...Total run time 30 minutes.....After 10 years I went to ZROD amsoil 10 W30 with new honda filter...It say 1.5 QTs with filter I have done that but not started it yet...Want to run it every 6 months and change oil ever 3 years...I want to pull plugs and put in the 10W30 maybe and let it sit with filter empty.... How many CCs?...Good Idea to leave the Filter empty?...will the oil protect anything in the filter.....? Appreciate all input and questions....