MerCruiser 4.3 TKS Leaking Oil - Missing Cap, plug or bolt

Running into an issue with my engine leaking some oil into the bilge. With a little help from a friend, we were able to diagnose where the oil is coming from, but unfortunately I don't know what type of of plug, cap or bolt that is missing. My oh so helpful marina won't even look at my image with out an appointment, which is 3 weeks out. Below are two images, a photo of the machined hole in the engine block where the missing part should be and a screen grab from a YouTube video that shows the missing part installed (looks like a bolt), right beside the drain plug. If anyone knows what this is, I would greatly appreciate it. - Cory

That is where the dipstick tube normally would go. If your is in the side of the pan get the plug from a good speed shop or install another dipstick tube

https://images.onesearch.com/yhs/se...=us&ei=UTF-8&fr=yhs-ono-ext&enct=p&encv=1_90&

Find a bolt to fit the hole... It should drop in, cover it with RTV and push it in. Let it cure for a day.

Thanks for the info! Makes sense after talking to a few more people. The engine was replaced by the previous owner, he installed it with a buddy who's a car mechanic. Not being familiar with that exact engine I guess they didn't realize there are two locations for a dipstick tube and over looked that. Going to measure and pick up a plug for it today. Thanks a ton!