willisja55
New member
Hi I have a 25hp mercury seapro 2 stroke and I was having an issue with it running very rough around idle last year . I noticed excessive shaking at idle and low speeds that would go away at higher speeds. This year I got it out to begin troubleshooting and after running noticed I have milky grey substance coming out the exhaust drains that I assume is unburnt fuel mixed with water. my initial thoughts were head gasket but I did compression test that is showing good. Not sure where to go from here other than removing head to check gasket. Did a pressure test on lower unit and it was fine. I also noticed I have water spraying out of a little spout at the top of my driveshaft housing which I thought was part of the exhaust separate from the water but maybe I am wrong and this is normal I just never noticed this before( if someone can tell me what that spout is I would appriciate it . I attached a few photos looking for opinions. I took the lower unit off and you can see the milky mixture all through the exhaust
