I was going to delete this post but thought maybe it could help someone else. I have a 1999 Mercury 200 efi. Recently started leaking fuel out of the vst from what I thought was the overflow. After a new needle and a cleaning it was still leaking. Well after a call to Chris Carson’s shop, one of his techs figured out my problem in about 15 seconds.
Chris and his guys rebuilt my powerhead a few years ago which has been great. So I called them for advice on this. He suggested removing my oil injection so we did.
after talking with them on the phone yesterday it appears the brass elbow in the bottom of the vst was where the oil line use to run to and the elbow is a check valve. Apparently my check valve is bad or gummed up causing it to drip fuel. Felt like a dummy but glad to get it figured out and it was an easy fix to plug it.