NAUTICAL SKILLS/ The Art of Diesel Maintenance
By Howard Cheetham
Many of you may know that we've had some engine problems with the old Cape Dory trawler we recently bought. During the inspection, before buying, the temperature alarm went off when the 200HP Volvo's revs went above 2300. Sure that it was a simple problem, we got a small discount from the seller which went on the first visit to Sailcraft. They found the raw water impeller cracked and barely pumping, and they replaced it – problem solved!
Well, almost, we now got to 3000 rpm before the alarm went off.
All the advice to this point, before going on the diesel maintenance course, was that it was probably build-up or a blockage in the heat exchanger. So I set about flushing the freshwater system but lost confidence when it came to removing the heat exchanger, and so I gave it back to Sailcraft. They did indeed find it dirty inside. They flushed and acid-washed it, but that still did not fix the overheating. And I'd now spent somewhat more than the seller's discount (getting close the the proverbial thousand in B O A T).
This is when we went to Mack Boring's diesel maintenance course. The hands-on activities did wonders for my confidence and the theory and process of "starting from the source and following it through the systems" was directing me to the thermostats next. I ordered new thermostats from Jarrett Bay and I set about replacing them. I deftly re-drained half the engine coolant, removed the thermostat cover and found one blown thermostat (photo).
Getting the new one in involved a lot more fumbling, but soon the job was complete and it was time to test it. At the dock I took the engine up to 4000 rpm without any alarm and watched the temperature gauge rise and then drop as the thermostats opened, then under load we took her out into the river and ran up to wide open throttle (3750 rpm under load) with the gauge staying below 190°F.
With muddled emotions of relief and satisfaction, we pulled in to Oriental marina to refuel, ready for a real spin up to New Bern the following weekend.
Which is the start of the next story…
Having refueled, I decided to alternate tanks to keep the fuel fresh, I turned the tank selection valve but forgot there is also a return line (Ed I believe I’m not the first to make this mistake!). We motored happily at about 12 knots all the way to New Bern, unaware that all of our fuel was being transferred to the starboard tank. On the return journey, just as I was questioning our distinct list to starboard, the port tank fed its last drops to the engine and with a couple of sputters the engine died.
About the Author
Howard and his wife, Ros, live in Chapel Hill. They joined the NSA in 2008 and sailed a Beneteau 37, “Island Dream,” until 2013 when they sold it and bought a 44' Nautitech Catamaran, "MISTO," which is currently being outfitted for cruising in the Caribbean in 2015 and the World ARC rally in 2017. For now, they sail "Hunky Dory," a 28-foot Cape Dory Flybridge Cruiser, out of Whittaker Creek. They were Cruising Commodores in 2011 and Howard was named Commodore in 2013.
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