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For anyone getting the alarm EMWT Level 1 or Level 2, more than likely the cause is plugged exhaust manifolds from running in water with lots of dissolved solids (ie high PH). The hot water in the exhaust manifolds causes the solids to precipitate out and the solids are left in the manifold which then clogs and doesn't allow enough water through.
Typically, this will not cause engine overheats as the coolant is still circulating and presumably both exhaust manifolds are not clogged at the same time.
This is what you can do to fix this problem:
- with the engine off, remove 1 exhaust manifold drain plug. Wrap a towel around it and start up the engine and catch the majority of the particulate that comes out. Run the engine until the water coming out is clear.
- put the plug back in and repeat on the other side
- then you can do an acid flush in your engine to remove the scale. I do the following steps:
1. Remove as much water from the engine as possible. Drain the exhaust manifolds, the heat exchanger and the pipes leading to the raw water pump. Put everything back together
2. Pinch the line going to the prop shaft seal with a clamp
3. In a 5gal bucket that you can connect to the suction side of the raw water pump, add 4 gallons of soft water. Then add 1 cup of pool acid (33% hydrochloric acid).
4. Start the engine and run it until the bucket is empty
5. Let the acid sit in the engine for 3 hours
6. Run the boat in the lake to remove any acid that hasn't been neutralized by the particulate
Repeat this if you feel that you still have particulate in your engine.
Another way to tell if you are starting to clog your manifolds is to closely watch your engine temperature. With clean exhaust manifolds, my engine was running (fully warmed up at 34mph towing a skier) between 158-160F. Once my manifolds started to clog, that temperature started to rise to 162, 165. I got the alarm at 167-170F. So if you watch that you will have some warning that you need to clean them - YMMV.
Cheers,
Paul
Typically, this will not cause engine overheats as the coolant is still circulating and presumably both exhaust manifolds are not clogged at the same time.
This is what you can do to fix this problem:
- with the engine off, remove 1 exhaust manifold drain plug. Wrap a towel around it and start up the engine and catch the majority of the particulate that comes out. Run the engine until the water coming out is clear.
- put the plug back in and repeat on the other side
- then you can do an acid flush in your engine to remove the scale. I do the following steps:
1. Remove as much water from the engine as possible. Drain the exhaust manifolds, the heat exchanger and the pipes leading to the raw water pump. Put everything back together
2. Pinch the line going to the prop shaft seal with a clamp
3. In a 5gal bucket that you can connect to the suction side of the raw water pump, add 4 gallons of soft water. Then add 1 cup of pool acid (33% hydrochloric acid).
4. Start the engine and run it until the bucket is empty
5. Let the acid sit in the engine for 3 hours
6. Run the boat in the lake to remove any acid that hasn't been neutralized by the particulate
Repeat this if you feel that you still have particulate in your engine.
Another way to tell if you are starting to clog your manifolds is to closely watch your engine temperature. With clean exhaust manifolds, my engine was running (fully warmed up at 34mph towing a skier) between 158-160F. Once my manifolds started to clog, that temperature started to rise to 162, 165. I got the alarm at 167-170F. So if you watch that you will have some warning that you need to clean them - YMMV.
Cheers,
Paul