Yanmar 6LP fuel filter

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Mystic Blue

Veteran Member
Sep 22, 2017
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1973 38' Hatteras DC
I have a Racor primary before the engine Yanmar filter. I believe the Yanmar filter is 2 micron and thinking of using a 2 micron in Racor. Comments?
You can use the 2mic, but I don't see much benefit in doing so. 2mic will clog faster and the net cleanliness in the injection pump won't be much better. And the Bosch VE pump clone (ND??) is not super sensitive. I use 10mic or 30mic on those engines. If the 10 gets cloggy, go to a 30.

Changing a racor offshore in a hot engine room while dipping rails then repriming the engine, that's low on the fun scale.
The general input from corporate Yanmar is to use a 30 Micron filter in the Primary Filter as depending on certain models 20 or finer can lead to fuel starvation issues as the fuel is being sucked from your tanks by (depending on the model) a mechanical fuel lift pump, the interesting thing is that for conventional engine models (non-electronic) they show generally to use 10 micron as the engine mounted filter, the 2 micron is the recommended filter for there electronically controlled engines,

That said with if using the 2 micron it's recommended to use the 30 micron as the primary unit.

The bottom line is really check with your operation manual as it will be specific as to your requirements for that engine ONLY,

Cheers Steve
Yanmar fuel filter

Mainship Pilot 30 - Spoke with Yanmar (6LP-STP) and they said the engine fuel filter (secondary) is between 2 and 5 microns and they recommend either 30 or 10 micron primary filter. So, yesterday I changed the Racor and put in a 10 micron. It was little brown but not bad after 134 engine hours since April this year. My tech manual says to change fuel filter every 250 hours or 12 months, and drain the water from the small bowl at the bottom every 50 hours. They did not recommend a 2 micron primary filter.
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