Lyman 23

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Minor Engine Maintenance (April 29, 2004)

Before using the boat for the first time, there were some minor engine issues to deal with. I had inspected the whole engine and fuel system carefully, and decided that, while most of it was in serviceable condition for the limited use we intended the first season, the short lengths of exhaust hose connecting the manifolds to the copper exhaust system needed immediate replacement. The original (to us, anyway) hoses were badly deteriorated and rotted.

I replaced the bad hoses with Shieldsflex wire-reinforced exhaust hose, 3-1/8" diameter. Replacement wasn't too bad, though I had some trouble with the T-bolt clamps I ordered--one size seemed too large to fully tighten; the next size down, which I ordered as replacements, could open barely far enough to even get around the hose. Eventually, I managed to get the hoses clamped securely in place. (Yes, I only have single clamps now...I realized after I ordered them that I didn't have enough, and will take care of that issue when I go through the engine extensively later in the year.)

With the exhaust hoses renewed, it was time to test-fire the engine for the first time. To prepare, I first installed two new batteries on board. Stupidly, when I picked up the boat from the boatyard in Massachusetts back in March, I had forgotten to pick up the one-season-old batteries that came with the boat. D'oh! I certainly wasn't going to drive back to Hingham for a pair of $50 batteries, so I bought new ones. The battery cabling was less than ideal (putting it mildly), but I thought it would bet me through the first season. (Have I mentioned yet how much I'm looking forward to really going through this boat?!)

Once the batteries were installed, all that remained was to provide a source of cooling water. With some effort, I removed the intake hose from the through hull fitting, and then inserted a second length of smaller hose inside the first, so that I could extend it far enough to reach into a bucket of fresh water (supplied with a garden hose). I filled the bucket with water and turned over the engine.

The engine turned over easily and fired quickly--I was thrilled! However, I was rapidly apparent that the engine was not sucking any water out of the bucket. I shut the engine down and began to investigate.

My first thought, logically enough, was that the raw water impellers were shot after a winter's storage and who knew how many seasons of use. So, sighing, I began to remove the water pump so that I could check the impellers. Having not done the chore on this engine before, it took a few extra minutes to figure things out; now that I've done it once, any future removal will be significantly easier.

The raw water pump contains two impellers, each providing cooling water to different portions of the engine. Upon disassembly of the pump, I found that both impellers were in good condition, though one side of the pump held a few broken pieces of some long-replaced impeller. I made a note of the impeller sizes and characteristics, for future ordering purposes, but decided to reinstall the same impellers, as they were in good condition. I did reverse the impellers, which changed the direction of the set of the vanes.

With the pump reassembled and reinstalled, I tried the engine once more. It fired eagerly at once, but still drew no cooling water through. I checked the various hose connections and then, in an inspired moment, took my garden hose and filled the intake hose with water, thinking that probably the pump simply couldn't begin suction. This did the trick, and when I started the engine it shortly began sucking in the cooling water in the bucket. Success!

The engine sounded excellent and ran very smoothly with no hiccups or hitches. Nice! The exhaust note was to die for--gurgle-burble-spurt. Awesome.