Boats like cars are mechanical devices. On a 30 year old boat which is maintained well things can still break once in while. While cruising down the river Dorothy noticed a strong oil smell when I checked the engine room, I found oil sprayed all over the port side of the engine room. I shut the port engine off to stop any damage from lack of oil. I wish I had taken a picture to show how bad it was. I finally found the oil fill cap had blown off. But what caused it? Checking the oil level in the engine it was way over the full mark on the dipstick and it was like water with a red tint and it smelled like diesel fuel. I determined diesel fuel had gotten into the oil so much that the crankcase pressure caused the oil cap to blow off.
I called an engine expert and he said the most common cause was a bad fuel pump. Great, I carry a brand new spare and it was easy to get to on the engine. We limped to a marina on the starboard engine. The next day was spent cleaning and replacing the fuel pump. I also had to remove the fuel oil from the crankcase. We took out 7 gallons of oil and fuel mix. The engine normally holds about 3 1/2 gallons of oil. Added new oil and ran the engines for a half hour. All seemed good. The next day while continuing down the river I shut the port engine down and checked the oil level. much to my dismay the level was way over the full mark once again. UGH!
Another call to the engine expert, he said the next place to look was the fuel return line on top of the engine. I removed the rocker arm cover and inspected the steel line running from injector to injector. I discovered a leak on Injector number 1. OK great just tighten up and we will be good. Nope, it did not work, still leaking. I took it apart and inspected the fitting and I cleaned the surfaces and reassembled. Still leaking fuel. Call the expert, and he suggested sanding the surfaces with fine emery cloth. Take it apart, clean, reassemble, still leaking. Keep in mind I am doing all of this while Dorothy drives the boat down the river on one engine. I tried a copper washer at the fitting. Copper is soft and should conform to any uneven surfaces providing a tight seal. Still leaking fuel. We reached our next Marina and both of us were so discouraged, we decided to sleep on it and get a fresh start in morning.
The movement of liquid in the bottom of the video is Diesel fuel dripping into the top of the head where oil should be.
After taking the fuel return line completely off I discovered that some where along the line I had cross threaded the top of the injector fitting. After some more phone calls we took the injector to a machine shop in the scary van and they tapped the threads straight. Back at the boat I carefully reassembled the engine and gave it a test run for an hour. No leaks, YIPPIE! Another oil change. The next day we did a short run of 2.5 hours down to the next marina. No leaks, YIPPIE!
Stripped threads in injector head.
We have been traveling for several days with no issues. So we are regaining confidence the problem is corrected. Back to enjoying the scenery and sunsets.