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Old 09-02-2012, 05:13 AM
Jon K Jon K is offline
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Day 3 of 7

So if I close the saltwater cock to heat up the engine, where does the steam come from?

1. Pressure test of FW side of heat exchanger failed. It won't hold 5 pounds of air pressure.

2. Going to sail today, visiting friends cabin on Gambier Island. Change hoses to send raw water pump output to freshwater pump inlet, through engine to exhaust manifold cooling jacket, change hose to send manifold outlet to exhaust. Two pumps, lots of cooling. Engine at or below 100 degrees.

Voila, raw water cooling. Left the thermostat out so temp never got beyond 100 degrees. Checked that water temperature gauge sending unit was still in the system, it is beside the thermometer housing and reads correctly.

3. Ran under power for 1 hour, stopped then ran again for another 1 hour. Dropped to idle to lower mainsail, engine stalled. (Stall on idle is ongoing problem). Engine temp read 140 degrees. Possibly less cooling during idle, engine still hot?

4. Waited a few minutes, engine restarted and ran fine for another 20 minutes, had dinner. Came home 1.5 hours, engine temp 100 degrees, no issues.

Stall on idle problem happened at 2 hours, engine temp 140. When engine was cool, did not fail as before. I think this points to a temperature related problem.

Neil, the cold coil resistance is 3.1 ohms. I just read the coil thread, will try to think about that. Measure when hot?

Great to be on the water today/tonight, full moon guided us home. Trying not to think about the saltwater cooling the engine.

Answer: Steam caused by freshwater and antifreeze pushing into the saltwater circuit at the exchanger and out the exhaust. Seems a likely scenario.

- Jon K.
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