Engine woes

Hi! Y’all:

Fair warning to those whose eyes glaze over during technical talk. That’s what this post is all about.

Two engine problems have occurred this year: fuel system and cooling system.

A fuel leak developed between the high pressure fuel pump and the flange for the return (to fuel filter) line. The neoprene gasket had lost its resiliency and needed to be replaced. While I dithered for several days, first making one, then deciding to use a $1.50 factory replacement, the fuel system was open to the atmosphere. Once I’d installed the gasket, I started the engine to test for leaks (there were none), let it run for 30 minutes, then shut it down. I didn’t use the engine for several more days. Before departing Vero Beach, I checked the engine oil level and discovered it was very high on the dipstick. I pumped out nine quarts of fluid (c.f. five quarts), a combination of engine oil and diesel fuel; thankfully, no water. I replaced the engine oil and we continued our journey.

Over the next several weeks, Mister P (P for Perkins) performed flawlessly. The unintentional engine flush with diesel-thinned oil had “cleared out the sinuses” and removed the long-standing clatter from the general direction of the engine compartment. Mister P was at his peak.

A week ago, I noticed the oil level was again high on the dipstick, although only slightly so this time. I had added a pint of oil only the night before, so I couldn’t be sure that I hadn’t overfilled the engine. I resolved simply to observe. I also sought advice on the cruisers’ net here in Abaco. Two people assured me that the fuel pump diaphragm had ruptured. One offered me his spare, if I needed it. That was extremely kind. Due to (Raven’s previous owner) Clyde’s forethought, there was a spare fuel pump on Raven. I fitted it, made sure that the engine would run, then opened up the old pump. The diaphragm was good. So, now I must again wait and watch.

The cooling system problem has been building slowly. Basically, the running temperature has been rising. During long periods at fast idle, charging batteries, the temperature remained at its normal 180°F. Underway, depending on load, it had been as high as 195°F, but sometimes it would run at normal. I checked the intake, the strainer, the impeller, and the hoses. All were OK. That left the thermostat and heat exchanger to inspect. I didn’t want to do this job, dragged my feet, looked for other causes, and denied there was any problem at all. On our way from Hope Town to Lynyard Cay, a 20 mile motor-sail before the wind, the water temperature rose to 200°F. This was beyond my comfort level. We were heading to more remote areas of the Bahamas and this problem was getting worse. I knew I’d have to solve it. Reluctantly, we returned to Marsh Harbour, backtracking 22 miles. It was worth it to have access to marine supplies and a FedEx office, in case I needed special Perkins parts flown in.

The NAPA store had a new thermostat but no gasket. I made one. I also dug out the special Perkins/Bowman heat exchanger rubber end caps I’d bought in Seabrook two years ago, also from NAPA. To gain clearance to lift the thermostat housing off the long studs, I had to remove the hose that carries antifreeze to the header tank. Ah ha! Lodged in the 90° elbow was a red worm, about 2’ long and ¼” diameter. Bits of rust and other debris had collected around it, cutting flow to about 5% of normal. The red worm turned out to be flexible gasket material that someone had been far too generous with during a previous repair. After reaming out the elbow and associated 2” pipe, I changed the thermostat, and exposed the heat exchanger core. It wouldn’t come out for cleaning but I easily passed a 1/8^th inch wooden dowel through every tube, so the raw water flow was clearly unimpaired. During reassembly, I replaced the end caps, one other rubber elbow, and one almost-broken-through worm drive clamp. I’ve learned that not all stainless steel clamps are made equal. Take a ceramic magnet with you to the store when you buy one. The best stainless steel is non-magnetic. Also, the clamps with pressed threads, rather than stamped-out threads, are usually of better quality.

Once all the clamps were tight, I topped up the antifreeze and then let everything sit overnight. I wanted to give the hoses and clamps time to settle in. Next morning, before starting the engine I checked all clamps for tightness. The engine started first crank, as usual, and came up to temperature – just below 180°F. I let it run for 30 minutes but never under load. (We are anchored out.) The temperature didn’t budge.

And so, the present crisis is over. Now, we are waiting for our mail from Texas and enjoying a little down time. Even allowing for unexpected problems, Raven’s maintenance list is slowly shrinking. If you think it’s tough to keep a car running, try a boat. Wear and tear takes its toll, as can be expected, but the environment is relentless in its attacks on the boat and everything on board, particularly the mechanical and electrical systems. It’s as well that cruising’s payback exceeds the work involved in staying afloat and underway.

Best regards,
Captain Dave