Thread: Water in Cyl
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Old 07-17-2006, 10:35 PM
Paul A Paul A is offline
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Water in Cyl

Don,

I have experienced water backed up into my cylinders (3 and 4). My 79 Cat 30 A4 had been running in the 160-170 range about a month ago with the Volvo thermostat in it. Reading your tech manual I caught a note to restrict the bypass line after the T fitting. I did that and it brought the temp down to a steady 140. At the same time I added the restricter, I also did an acid flush (it had been about 3 years). Everything appeared to work well but I did notice that I wasn't getting near the water coming out of the engine that I did prior to this work. Eng Temp was great though.

The next time we took the boat out I noticed some steam in the exhaust (something I hadn't had before). I continued to use the boat on the weekends with no temp problems or noticable engine problems until last weekend. After motor sailing for a a couple hours the engine quit running. when I went to look I had water coming out of the throat of the Carb. I have never had a problem like this motor sailing before.

I pulled the plugs, filled cyl with MMI, cranked with H2O intake closed until water was out of cyl. I ran a compression check on all cyl. 4=120, 3=90, 2=115 and 1=120. The exhaust manifold was also full of H20. I pulled it off the engine, drained the water and inspected it. (it was replaced 2 years ago) I ran water through the upper portion with good flow out the exit port and no noticable water going into the dry section. I reassembled the engine and ran her for 1-2 minutes at a time with water intake closed while changing the oil until the oil looked clean. I also disassembled my entire exhaust to look for restrictions or blocks. I found nothing.

I opened the raw water intake and ran the engine noting again steam and less flow of water than normal coming from the exhaust. The engine backed up with H2O again. I repeated the steps above less the compression check and exhaust removal.

I then removed the thermostat and started the engine with water intake open. I finally got the correct amount of water leaving my exhaust that I have been used to seeing for years with no steam. The engine shut down about a minute later and the cyl (3, 4) and the dry side of the exhaust manifold were full of water again???

Would a thermostat cause this problem? Engine temp was always good following the addition of the restricter and the volvo thermostat. would the restricter cause this? Could it be the acid flush? The engine has run great for the 4 years I have owned the boat less having to replace the thermostat and exhaust manifold for a hole in it.

Any suggestions?

Paul
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