Tohastu 20hp Gear lube incident and oil leak

[baotingshallow]

I have a 20hp Tohatsu 4-stroke and recently had an issue with an oil slick when launching the boat. I discovered fuel was getting into the oil, so after some research, I replaced the fuel pump and installed a new O-ring. I noticed the fuel bulb could now get fully hard, which it hadn’t before. I started an oil change with a new filter, ran the engine on muffs, let it settle, and went to top it off. By mistake, I grabbed gear lube and poured in a decent amount, then ran the engine again before realizing the error. I immediately drained it, put in new oil, but didn’t change the filter because I didn’t have a spare. When I ran it again, the water was extremely hot and the engine was overheating. I’m letting it drain overnight and plan to add new oil and a filter tomorrow. Also I’m not sure the fuel pump was even the problem, as I saw a small amount of oil coming out the bottom while running it on the muffs.

 

[Chris1956]

I would remove the filter and empty it. Now reinstall it and add the correct amount of new motor oil. The residual gear lube should not affect it much. Remember STP, motor honey and other motor oil additives are simply thicker oil, as is gear lube.

Now diagnose the real problem.