One strategy is to use 2 micron in your Racor
and your Yanmar secondary filter won't need to be changed for years. A few drawbacks:
Yanmar says this can void your warranty because it puts load on the fuel pump
. But the typical Racor 500 is rated for 60GPH. A small sailboat engine isn't drawing 1/20th of that. I have a pressure gauge on the Racor with a maximum pressure indicator. I don't see any pressure difference on the gauge between a 2 and a 30 micron filter. If your engine is out of warranty, you don't really care.
While the gauge on the Racor tells me when to change the fuel filter, the Yanmar secondary has no gauge except maybe a water alarm
. Your first warning of a clogged secondary filter is when the engine loses power. Try changing this filter in a bad sea! I consider this is a safety
Your 2 micron Racor filter will clog more quickly than a 30 but I can go through a lot of Racors for the cost of one Yanmar secondary and the Racor is way easier to change. I only have filter problems in the rare case when I've taken on bad fuel as I religiously use a biocide like Biobar Jr to keep the tank from growing junk. Normally, I change the Racor filter at every oil change
with the gauge still showing no significant pressure.