The primary fuel filter on a diesel engine has always been a mystery to me. On my old sailboat, a 1985 Hunter 34, which I co-owned with my good buddy Larry, it was a thing of mystery to both of us. Once, he decided to clean the filter right before we left on a trip to the San Juan Islands. Larry took the whole filter apart and cleaned it right up – unfortunately, neither of us knew anything about bleeding the engine. We started the boat up alright, let it idle for a bit, then started to cast off right when the engine quit. No fuel. That led to a whole cascading series of event too embarrassing to relay here, but ended with the engine filled with salt water, and, nither of us knew it! Some lessons must be learned the hard way.
Another time, MS and I were off the coast of Marrowstone Island, about 25 miles from Seattle. We were in fog, the GPS was saying that we were two miles inland, and a big tanker was barreling down on us and honking. Of yes, we were surging in the waves, kicking up all kinds of gunk in the tank and, naturally, the filter clogged at the worst possible moment. The engine stopped running right, and billowed white smoke (what the hell does that mean!) and we had no engine power. I thought it was a filtering problem, but had no idea what to do. We raised sail in about 5 knots of wind, drifted out of the way of the tanker, and pondered the fuel filter.
So, our beautiful new Malo 39 came with a fuel filter called a Lucas filter. It was solid, round, and did not look easy to open. Nobody in Seattle had heard about it. Mike explained to me that the Lucas met EU specifications because it was solid and fireproof. Nobody I talked to knew about replacement filters.
Also – it was English ( as in British). I had a British motorcycle once (1966 Triumph 650 cc Bonneville) which I spent my entire youth trying to keep running. Since then – I have a distinct mistrust of British engineering ( I also had an Italian espresso maker that tended to explode and send coffee everywhere, but that is another story).
So – that filter had to go.
We choose to go with a Racor 500 MA. This is a quick change filter where the element drops in from above. This keeps problems with bleeding the engine to a minimum. We also installed it with a vacuum gauge. This allows for reading the back pressure on the filter. When it gets up into the yellow area, you need to watch out because the filter is getting dirty. You probably can not see this happening, even though it is a glass filter in which you can see the diesel fuel. I think that if the fuel is so dirty you can see the dirt in it, you probably have a bigger problem than changing the filter element.
This was a very easy, $200 upgrade, and the Racor slipped right into the area where the Lucas was. The little aluminum bowl at the bottom is a flame guard for meeting US Coast Guard regulations, not draining the filter. To do that you open a drain on the bottom and spill the fuel everywhere, like you have to do with every other filter…..
Another problem was bleeding the engine. We solved that by installing an inline automobile fuel pump. This $80 pump goes right in line with the fuel line. Flick a switch and it pressuries the filter and bleeds fuel down through the secondary filter. I got this idea from a great book by Bill Seifert (former editor of Practical Sailor) called "Offshore Sailing – 200 Passagemaking Tips". This is a great book full of all kinds of practical information. He is a gourmet, and even has some recipes in the book which the Propane Chef approves of – though they are a bit simple, and velveeta cheese is in one of them!
The pump is the copper looking cylinder to the left of the circuit box. The switch is mounted in an external outlet box. I took a diesel maintenance class in which the instruction recommended this sort of arrangement, though he preferred it on a bypass (two – three way valves connected by a bridging line) As you can see, there is no way to do this, since the space is tight. If this pump fails, there is a sight possibility of line blockage, though it is very slight.
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