Engine Update

This blog post gives a summary of what was ACTUALLY wrong with our engine leading up to this point. It conveniently compresses two weeks of troubleshooting down into one post. If only I had read this post before starting the process…

When we suspected that our raw water pump was leaking into the engine the first step was to disconnect the pump from the engine so that no more water would get in. I continued to monitor the engine oil level even though we weren’t running the engine while waiting for the new pump. Even with raw water pump separated from the engine our oil level continued to rise! This meant that we must be getting water in through our exhaust system. As soon as I disconnected the exhaust hose leading to our muffler I found our “smoking gun”. I had finally found the real problem. The exhaust hose was full of water and it was at a level high enough to be running into our exhaust.

The short version of this problem is that the exhaust system was installed improperly, and has been allowing saltwater into our engine for a long time.

The long version is that three things were wrong at the same time which allowed water to backfill into the engine.
1. There was no anti-siphon loop on the water injection into the exhaust. This should have been installed with the engine.
2. The water lift muffler was mounted higher than the exhaust outlet. This is supposed to be at least a foot lower.
3. Our raw water pump was allowing a trickle of water to leak by when the engine was off.
The combination of these three items allowed the water into our engine.

This video shows these parts of our engine.

Once the problem was located we took steps to fix the situation. All of our resources indicated that with this much water coming in through the exhaust our engine should be at a high risk of “hydrolock”. Hydrolock is when one or more cylinders inside the engine are filled with water and since the water can’t be compressed the engine can’t turn over. Not wanting to do any damage to the engine trying to start it. I disconnected the exhaust system from the engine, and flushed the oil system. I moved the oil through the engine by turning the engine over by hand using a large wrench. After cleaning the lubrication system thoroughly we refilled the engine oil including a dose of Marvel Mystery Oil an oil additive designed to help clean the engine. I reconnected the muffler at a level lower than the engine exhaust and ran the engine long enough to get it up to temperature and drive out any residual moisture. The engine started much easier and ran smoothly!

An Endeavor 37 here in St. Mary’s also has a Perkins 4.108 and we went over and listened to his engine to make sure ours wasn’t make any highly unusual noises. The owner Josh was nice enough to start his engine up for us and let us listen at a variety of RPM’s. Josh’s engine was just as loud as ours, and sounded nearly the same!

After I setup a proper exhaust system our engine will be running better than ever. Hopefully having saltwater in the system hasn’t added too much wear to the engine.

2 thoughts on “Engine Update

  1. Now I understand the true meaning of the slogan under your blog title. Good for you! You did indeed figure it out…..:-))

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