Fuel Filter Sizing

[johnmurray]

My boat (the A-30 FC with the Yanmar 315 engine) came equipped with a primary Racor fuel filter, model number 900MA. The element in the filter was a 2040SM which I have since had replaced once with the same size and later discovered was a two micron filter.
When shopping at the Racor booth at the Toronto boat show, the Racor rep told me I should not be using a two micron filter as the primary, but rather a ten micron filter which is number 2040TM. (They also have a 2040PM which is 30 microns). He said that the secondary filter on the engine was probably a two micron filter and the primary should not be as small.
I have also had the secondary engine filter replaced once. It was very difficult to get at and remove and it showed no sign of having collected any reidue. (Presumeably nothing got past the primary filter.)
Would it not be better to have as small a filter as possible as the primary, particularly when the secondary is so hard to get at?
Does anyone have a view on this matter?

[RicM]

You might want to take a look at www.boatdiesel.com. There is tons of material on different filter setups. The website is $25 to join, but well worth it if you are new to diesels.