USPS Engine Maintenance Student Manual

On-the-job education

Postgraduate Engine Maintenance

After completing the 2 USPS Engine Maintenance modules in late May, I commissioned my 36-foot cruiser, ready to enjoy the boating season. Our family’s first voyage would be to the District 1 rendezvous at Essex Island, Conn.

We were between the bridges on the Connecticut River when my daughter, Lesley, shouted that smoke was coming from the bilge. My son, Frank, countered that it was steam.

I shut down the port engine, because the steam was coming from that side. But the steam didn’t stop. A glance at the gauges showed the starboard engine at 240 degrees, so I shut it down.

We cautiously lifted the bilge covers and confirmed that the starboard engine was the problem. We limped back to the dock on the port engine, shut everything down and continued to Essex by land.

When I got in the bilge on Monday, I remembered our class discussions on impeller pumps and risers. Either could be the problem. After checking my maintenance logs, I decided to change both.

When I disassembled the impeller pump, it was full of neoprene particles, which meant some of the debris was in the system downstream. I back flushed it and collected what I thought was all the impeller debris.

I installed a new impeller but not without challenging my athletic flexibility. I spent most of the day with 1 leg around a support pole and the other cramped into the generator. I thought I would have to call 911 to get out of the bilge, but I finally managed to stand. The risers were next.

My bilge covers lift off, granting easy access to the risers. The marine wholesaler wouldn’t sell directly to me, so I bought 4 units off the Internet for $500 plus $8.65 shipping. They arrived 2 days later. I installed them without any real problems except for a few bruised fingers from trying to twist off hoses and line up 3 gaskets under each unit. When I tested the engine, it was still overheating.

After holding a dockside conference with 8 fellow boaters, I received myriad suggestions. As the pump impeller had disintegrated, I would have to back flush everything downstream again, first the oil cooler and then the transmission cooler.

I back flushed the units—searching the water like I was panning for gold—until I had 3 bucketfuls of clear water. You should have seen the contortions my aged body endured under that 330-horsepower V-8. I removed hoses and clamps that hadn’t been touched since 1990. I should have had a camcorder. Or maybe not—my performance might have been hilarious, but my language wasn’t.

I finally got out of the bilge and back to the helm. The engine started easily, and I sadly watched the temperature gauge climb past 190 degrees. Isn’t boating supposed to be fun?

The next culprit had to be the heat exchanger. I looked at it for 2 days, growled at it another day, and finally drained the cooler and started the extraction. Milking a bull would have been easier. When I got it off the engine block, I removed the cover and was astounded to see how small the tubes were and how readily they trapped bits of neoprene from the disintegrated impeller.

My friend, Scott, at Oak Leaf Marina, sent me to a repair shop in nearby Madison. When I got down there, the owner looked at my exchanger and simply said, “Ready Friday or Monday?” I asked if I was the only goof who did this, and he assured me that he takes care of many fools on a weekly basis.

Confident that the problem was solved, I picked up the exchanger. With the exchanger back in place and a new impeller in the pump, I started the engine. Soon, it was almost as hot as the exhaust, and the indicator rapidly passed 200 degrees.

As it turns out, the impeller pumps are unidirectional and must be installed consistent with the engine rotation. I went back to Scott, who sold me 2 impeller kits and explained that by rotating the pumps 180 degrees, I should align the intake and outlet to match the engine rotation.

I took off the pumps and installed the new kits, and now the engines run cool.

If you think this story was messy, just wait until I tell you about replacing the holding tank that sprang a leak.