Thread: Fuel Filter
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Old 06-28-2014, 05:34 PM   #25
Chrisjs
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Join Date: Oct 2007
Posts: 789
After all the comments about short run hours, I pulled out my log book today and checked filter change intervals. A number of different scenarios came to light!! There were some proactive change-outs before longer voyages to avoid the need to change underway - better to be prepared!! There were change outs after our tanks were cleaned when we first bought the boat. There were change outs with new fuel and most recently change outs with aging fuel. Hours run between filters varied significantly. Initially with clean tanks and fresh (road tanker) fuel we were getting 75-100hrs. Then for a period with barge fuel (fishing fleet and Ft. Lauderdale barges) we were were averaging more like 60+hrs. But we were also getting spikes up to 90hrs. Most recently (past 3 years) averages are running higher and as high as 150-200+ hrs with older fuel. My non-scientific conclusion is that there is a lot of variation between dirt handling capabilities of the 2 micron Racor 900 filters. I did drain tanks a couple of years ago and did not get any sediment or black particles in the final dregs.

I did also confirm that the Cummins 5.9 6BTA pump spec is 29GPH, so, for example, 100hrs of run time equals almost 3,000 gallons filtered.

Can't explain the lower numbers. If it was dirty fuel, then we cleaned it up just fine, because everything runs great!! I also think that there are most likely "tight" Racors and "loose" Racors. These are not precision items. I do know something about filters - I worked for a precision filter company selling ultrafine filtration to the pharma and electronics industries.
Last comment is that I do not really care whether I get 50 or 250 hrs provided the filters do their job and the Cummins is happy!! Plus I also have an on engine 2-micron filter after the Racors - belt, suspenders and jock strap!!.
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