Oil injection removal question...95 mariner 175

[Embrey]

The guy I bought this boat off of a guy, and he said he had deleted the oil injection and mixed it himself. Which is what I have done all year. but I noticed gas fumes when opening the hull and some rainbow colors when draining the boat..lol. So I got to investigating. He had this tank cap stuffed up in the boat. One line t's into a line off the oil tank that is on the motor. The other goes into the bottom side of the block on a fitting. And he has bypassed the oil line on the other side. Now, I can hear like a check valve sucking sound coming from that cap when its running. I assume I need to plug that hose on the block and get rid of this tank cap. What is it for actually since it has a tank on the motor? Reserve tank? I know what i think needs done, but I'm not an expert on oil injection on these and I don't wanna end up frying pistons from blocking something off. And as of now, the motor runs great except if you take off slowly it will surge until it reaches about 20-30 mph ,then smooths out perfectly. If you stab the throttle its fine,and idles perfectly always and starts good. Just want this deleted right.