Marine water sepperators?

Question

can a diesel water sepperator be used for a gas outboard engine, what is the differance. I know that a gas cant be used for diesel but can diesel be used for gas? why?I THINK I KNOW THE ANSWER BUT JUST WANT TO KNOW FOR SURE THANKS

Answer 1

You asked this question a few days back and gave best answer to the wrong answer! The answer is still no, they can not be interchanged. One reason is the micron or filtration size is different, the other is that diesel filters are not rated for gasoline, and often have clear bowls that again are not rated for gasoline.

Answer 2

The answer you got a few days ago was correct. A diesel filter has smaller micron holes in them to clean the fuel even cleaner than a gas filter can get it, and separates water from the fuel.

Diesel injection systems on a diesel engine can not tolerate dirt or water in the injectors, it will score (damage) them and makes them stop operating and very costly to repair/replace.

Gas engines are still in need of clean fuel too, but they can tolerate a lot bigger pieces of "Dirt" in the gas and a little water (drops of water), with little harm to the engine or fuel system.

You can safely use a diesel filter on gas, but not a very good idea to put a gas filter on a diesel system.

The down side is that the finer filter on the diesel filter will need to be replaced more often because it gets clogged up with dirt faster because it catches more. Even with that, I prefer to install them on all my engines, filter elements are much cheaper in the long run that excessive wear on either system.

There are some manufactures that don't recommend that you use their diesel filters for gasoline because they use a cheap plastic bowl on the bottom and the gas will eat it. I haven't run into any of those brands in a few years now.

You can go to:

http://www.parker.com/racor/marine2.html

http://www.parker.com/racor/gas.html

This is one of the Racor filter sites (Racor is one of the top Marine brand filter companies), you will find first one for gas or diesel, the second site for gas filtering only (because it isn't fine enough in filtering).  

For Coast Guard requirements, on some they require a steel bowl for gas on comercial vessels due to gasoline being a fire hazard on a boat if the bowl gets hit and shatters.  The filtering elements are whatever size micron hole size you want from 20 to 2 micron.  But many of the gas filters have clear bowls also as the web site shows, but use is dictated by Coast Guard Regulations, not because they can't do the job on boats.

The downside to using a diesel filter over a gas filter is that they cost more....