Originally Posted by Chuteman
My notes say Yanmar has 10 mic at secondary (engine mounted - spin on) filter for my 4JH4AE engine and many others.
BTW - cautions(from Yanmar) about using less than 10 mic that it could cause fuel starvation - their idea is not to use filters as default for proper Fuel Purchasing
Unfortunately, I could not find spec details on part sites either - just listed part #and engine(s) where the part fits....
Here's a similar thread else where that confirms 10-15mic on a Yanmar engine scroll down to red (several) comments
SailboatOwners.com - Yanmar filter micron size?
I've emailed Yanmar for a confirmation. If it is 10-15 µm I'll be doing a modification on my 3JH.
I use to work in Fleets & Facilities for the City government
, which did a lot of governm't R&R. I did the maintenance
on the fuel sites and worked with the mechanics with a lot of the fuel problems. By the time I was out of there they wouldn't run anything larger then 5 µm filters on the trucks and other diesel equipment
. At the fuel sites I would change out a 30 µm filter if it's flow rate got below a certain amount. And the smaller diesel equipment
(mowers, generators, small tractors) they went down to 3 µm.
In the shop you could see the sticky injectors that were laying around from the old days. If you could get them apart, you could see the scoring between the surfaces. An injector for a large Cat or Cummings wasn't cheap
so they were willing to buy the filters by the truck load.
Back pressure gauges are very important. I relied on them heavily on the trucks.
If there is worry about rupturing a diaphragm
in the lift
pump then a back pressure gauge would be a must.
It's those fine particulates that wear out the hardened parts of a hi-pressure system.