Picked up a 96 ranger with a 200 efi. Supposedly the guy I bought from had just put a check valve on the oil pump the day b4 I picked it up. 2 Nd trip to lake wouldn’t start, took to a shop and only thing they found was the oil mixture was very heavy. I informed the mechanic I would be removing the oil pump and pre mix my own and until I got the part he suggested when not using to crack the cap on the oil tank. This past weekend I had issues. Was in a lot of no wake zones and when I would try to plane it would just bog down, after a minute sometimes a couple it would take and run fine. Acted like it was sucking air. Could I still be getting to much oil?