Micron Rating of Inline Filters..?

[kraw2]

What is the micron rating of the replacement plastic inline gas filters used under the cowlings of outboards? I can't find the answer anywhere.

Just pondering..??

[fitz73222]

For Mercury carbureted engines they are 70 microns.

[fitz73222]

Thats for a factory replacement filter I should add.

[wingtime]

Never seen one with a rating on them.  I doubt it is very fine due to the limited filter surface area.  Those are only meant to catch big junk such as rubber bits from your hoses or fuel pump.

Ahh never mind Fitz knows!  

[kraw2]

That's basically what I am tying to find out. Are these cheap filters really necessary on older 2 stroke engines using a 10 or 2 micron fuel/water separator before the engine.

[fitz73222]

That's basically what I am tying to find out. Are these cheap filters really necessary on older 2 stroke engines using a 10 or 2 micron fuel/water separator before the engine.

You are probably right; they're not necessary going to capture anything behind a 2 or 10 micron filter. When I change them every 100 hours or so they always look like new when I cut them open for a look see. I think their primary purpose is to give the engine some line of defense against the majority of the boating public that has no clue what they are doing and will run an engine till it quits rather than spend a penny on maintenance.

[wingtime]

I like to run the clear type you can see the fuel element inside.  This gives me several advantages.  It allows me to see how much fuel is in the lines when I prime the motor before starting.  I can see the color of the fuel so I know the oil injector pump is working.  I can see if there is anything contaminating the fuel after the 10 micron water separating filter.  This could come from bad fuel lines, oil lines, the diaphragm in the fuel pump etc..    So do you need one...  probably not....  but I think it is cheap insurance.

[pigbike]

They could help if a small piece of rubber separates from the fuel line after the 10 micron filter. My filter has 4' of fuel line after the water separater filter.