FUEL FILTER QUESTION

[Tantramar]

I have a Volvo Penta D-130 engine in my sailboat and it runs perfectly. The fuel was polished a few years ago, I always add a splash of biocide when refuelling and it is very clean. Volvo recommends changing the engine fuel filter every 200 hours and I have been changing the Racor filter at the same time. The sight glass on the Racor filter is always clear with no water, sludge or other debris. I am wondering if changing these filters at this frequency is necessary given that there is very little crap being captured. My neighbour has reduced his filter changing to once every few years or about 500 engine hours. Is changing the fuel filters at the recommended interval really necessary?

[S/V_Surya]

As someone who has had to change the filters at the most in-opportune time I would say yes. I had fuel polished and got about 250 hours before clogging. This a 30 micron filter. Yanmar service guy said 100 hours is recommended. You do not want to be in a tight situation and have your engine die.

[Pete7]

Cheap insurance policy to ensure you don't have a problem. A blocked filter just as you arrive in a strange marina or harbour does tend to add to the excitement. In our case it was weed in the water strainer but I could have done without it.

Pete

[Wotname]

Look at it this way, changing a fuel filter is maintenance. There are only two types of maintenance, scheduled and unscheduled; i.e. preventive or repairing something that has failed.

Both types result in working equipment but you get to choose when it is carried out; either at your convenience or when the equipment breaks...

So your question is "do I extend the interval between the scheduled replacement of the fuel filter and risk possible unscheduled maintenance (unexpected blockage and thus engine failure) or not"

My answer is "the engine fuel filter is doing very little work given you have Racors upstream so perhaps you could get away with saying doubling the interval of the ENGINE fuel filter but what do you gain - really only halving the cost of engine fuel filters. By replacing it at the same time as the Racors, you gain the peace of mind that you have taken every possible step in ensuring CLEAN fuel is being delivered to the engine and engines love clean fuel; in fact, they die without it. Additionally, the mere act of replacing the engine filter helps you in eyeballing the general condition of the engine and spotting potential problems - small leaks, wears, corrosion etc. Nothing like being up close and personal with your engine

[dlymn]

We change every 100 hours. We have a pair of Easterner filter separators and the standard engine mounted fuel filter. All these filters are in the bilges. I inspect the easterners regularly because the filter is fully visible. Usually they look fine, but a visual inspection in the bilge is not what I would call thorough. Occasionally I have found rubbish on the filters when before there was none. I think it might be caused by adulterated fuel or by sailing in heavier seas than normal and this sloshes the fuel around. The point is that it's hard to be certain that filters are actually perfectly clean and it's hard to predict when a contamination event might occur. So, to be safe we change them over even if they look OK.

[Tantramar]

Thanks for the responses. I believe everyone seems to think that the filters should be changed as per the manufacturers specifications. I am OK with that. Before the fuel was polished and I started adding biocide I became very familiar with "unscheduled maintenance". Before I figured out what was going on I was changing fuel filters every 30 engine hours or so and never at a convenient time.
I will take your advice and stick to the 200 hour frequency even though the filters are probably nowhere near plugged.

[jeremiason]

I had three fuel tanks on my Catalina 470 with one Racor 500 on each tank. The reasoning was that if one filter went bad under way, I could switch tanks and soldier on. That also allowed me to change filters on my terms, not the ocean's. By switching returns, I could also transfer fuel from one tank to another.

Since the fuel tanks were new and not likely to have any debris, I started using 2 micron filters in the Racor filters and also a 2 micron filter in the engine's fuel filter. I never had any problem with those and used them for the ten years I owned the boat.

One advantage was I had vacuum gauges on the Racors. This way instead of using engine hours, I used vacuum pressure as a guide for changing filters. I was getting about 300-400 hours out of each filter using this method.

I changed out the engine fuel filter at 500 hours, reasoning the primary filters were doing all the work.

Never had a fouled filter in 10 years and 1500 hours of motoring.

[Lepke]

Traditionally diesel engines had a 30 micron primary filter and a 10 micron secondary. Once your tanks are clean you can run a 2 micron in the primary, I have for the last 5 years. Mounting a vacuum gauge between the primary and lift pump will show when the filter is starting to clog with plenty of time to change. If necessary put in an electric sender with the gauge at the helm. I do 500 hours on primary and could go more. That's burning about 5000 gallons and about 20,000+ passing thru the filters.
I use a 2 Racor system for primary so filters can be switched running. I always use the recommend dose of bio conditioner and started with a triple dose when I bought the boat. I didn't get into the tanks for a couple years, and when I did, no sludge or water. The tanks were clean. (The boat had sat 6 years prior) Most diesels pump several gallons an hour more than burned, returning the excess to the tank. Fuel gets filtered many times before finally getting burned. With proper conditioners and filters, polishing takes place every running day. Buy your fuel from volume sellers.