|The original impeller at circa 20 hours runtime. One of those vanes is partially torn at its base.|
Investigation via eyeball confirmed I wasn't getting water through. Generally, I would make the following assumptions:
- Some sort of blockage in the seacock or standpipe, up to and including "forgot to open engine water cooling seacock". (This was ruled out quickly).
- Some sort of blockage in the hose to the Perko water strainer I've described before.
- Some sort of airlock, probably at the "top" of the cooling circuit (which would be the Perko) keeping water out of the "down" side.
- A failure of the impeller to impel or of its related camshaft.
- All of the above.
- Using a bottle washer on a stick, I plunged the standpipe. Some, but not much, vegetation stuck to the bristles.
- I removed the hose going to the Perko and gave it a good blow. Attached as it was to a column of water in the standpipe, it amusingly spat lake water back in my face. Apprised of various laws familiar to Boyle and Torricelli, I learned the hose, at least, wasn't particularly mucky or occluded.
- I opened up the Perko strainer and examined the filter element. Quite a few small weeds, broken shelly bits and some sand were visible; I disposed of them. Probably from last fall's grounding, I thought.
- I puled the impeller. Huh. Signs of wear, but not failure.
|Although one should avoid running dry, this version will do better.|
|Yeah, it's time for Speedseal to get my order.|
|Good to go with the right gasket.|
|An argument for removing the impeller over the winter, I would think, but that complicates the winterizing a bit.|
|The red/silver stick to the right is a large dental-type mirror. This gets used a fair bit aboard.|
|Restored! And yes, not dropping any of the six slot screws (why?) into the bilges was in fact an achievement.|
Did I just lose prime? Was it the damaged vane? Did the vegetable and mollusk muck play a role? I can't say if there was one cause or several in concert. But I feel better that the problem of "no throughput" led me to a methodical process, because having plunged, blown and mucked out, I feel I'll likely get better, longer service from the new impeller.