Friday, October 26, 2007

Fuel Issues

Changed Racor Fuel Filter
Changed Secondary Fuel Filter
Changed Crankcase Breather
Changed Air Filter

Replacing the shift cables went very smoothly, so my father-in-law and I finished that job faster than I had anticipated. That left time for a little more maintenance before Michele and her mother arrived for our trip over to Cambridge.

I've had some concerns about our engine recently. There was a noticeable power loss and an increasing amount of grayish smoke at cruising speed. That could be a sign of serious trouble (worn rings, bad or dirty injectors), or possibly just a fuel problem. I was considering calling a Volvo diesel mechanic, but wanted to get all the filters changed out first, to determine whether it was just a fuel problem.

We quickly changed out each of the filters: the Racor primary fuel filter, the secondary fuel filter on the engine, the crankcase breather, and the air filter. During this process, I also discovered that my prior difficulty bleeding the fuel lines wasn't a problem with the lift pump after all. Instead, it was "operator error" -- i.e., I wasn't doing it right. The pump lever has some play, and I was only moving it within that range. To actually work, it needs to be pushed down beyond that range, at which point it springs back up. I was very pleased to learn this and gain the peace-of-mind that comes with now fully understanding the bleed process in case I ever need to do it while out on the water.

I'm happy to report that this effort made a huge difference in engine performance. Our speed was back up, the engine ran smoothly, and the smoke was virtually gone. We're still only hitting ~3400 RPM instead of our rated 3600 at wide-open-throttle, but that may just be a result of marine growth on the hull, so I'll wait until we launch in spring with fresh bottom paint to determine whether there's a problem.

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