Fuel Filter/Separator Question

[daniel123]

An certified Evinrude mechanic looking at my 1999 Johnson 115 noted that I had installed a Moeller cannister-type fuel filter/water separator in the fuel line (replacing a much smaller Racor-type fuel filter that I assume, since it was behind an inspection plate on the starboard wall aft, it was original equipment?) and the mechanic commented that Evinrude didn't recommend after-market fuel filters, that it could affect the engine's performance, and that the outboard's built-in fuel filter would to the job just fine. I thought any filter/water separator was a good addition and had no idea installing one would affect the outboard's fuel flow/performance. Who's right?

[Bergertime]

Daniel,

I have both a Racor filter/water separator and inline filter under the cowling.  Now I am no mechanic but I have not noticed any performance issues related to fuel flow.  But then again, both were one on my boat when I purchased it from the PO which I promptly replaced.  The existing Racor unit looked like real crap and the filter was full of debris.  It could have been installed at the factory from its appearance.  Maybe Bob can weigh in on if they were part of the original rigging.  However, I have never heard that they were a bad idea or a risk for performance if properly installed and maintained. Maybe a search out on THT may yield some differing opinions.  I am interested in hearing what our groups thoughts are...

B

[seabob4]

Dan,
The ONLY O/B that I know of that does not want you to use an external fuel/water separator is the Verado.

You get some interesting info where you live...

[cdoyal]

Hopefully you guys don't mind me jumping into this thread with a separator question. I have a Raycor filter with the plastic bowl screwed onto the bottom. Having never had one before, I have a question: Is the bowl ONLY supposed to contain water? Mine is filled with what appears to be straight gas. I drained it a couple of weeks ago and after 4-5 hours of run time, it's completely filled up again. Is this normal?
Thanks!

[Capt. Bob]

Yes,
Very normal.
Fuel is of course in the filter above and in the bowl below. The heavier water passes down through the filter and settles to the bottom of the bowl. If water is present in your fuel supply, you can now see it and then drain the water from the bottom of the bowl (via the drain tube) with a minimal loss of fuel.

Good luck.

[cdoyal]

Yes,
Very normal.
Fuel is of course in the filter above and in the bowl below. The heavier water passes down through the filter and settles to the bottom of the bowl. If water is present in your fuel supply, you can now see it and then drain the water from the bottom of the bowl (via the drain tube) with a minimal loss of fuel.

Good luck.

I guess it's a good thing that I only see gas in the bowl and no water!

[fitz73222]

and the mechanic commented that Evinrude didn't recommend after-market fuel filters, that it could affect the engine's performance, and that the outboard's built-in fuel filter would to the job just fine. I thought any filter/water separator was a good addition and had no idea installing one

The only way a filter can impead the performance of an engine is through restriction. So unless your 115 is pulling 40 gallons per hour (which is what most filters are rated at) I'd say you have nothing to worry about. I'm always very curious to hear the reasoning behind "mechanics" making statements like that and I get all ears when they roll out the explanation.

[wingtime]

All my outboards have a water separating filter installed before the motor and a inline filter between the fuel pump and the carbs.

On the Racor question, yes the bowl on the bottom should be full of fuel.  Water or sediment will show up in the bottom of that bowl.  When it does just drain it off using the petcock.   Note: if you running ethanol fuel the water will not show up in the fuel since the alcohol will absorb the water.  At least until it reaches the saturation point and it phase separates!

[dburr]

the mechanic commented that Evinrude didn't recommend after-market fuel filters, that it could affect the engine's performance, and that the outboard's built-in fuel filter would to the job just fine.

Who's right?

Not him Dan, not him.....

Glad SB mentioned the Vrod, I have no experience with them.  Every normal engine I have ever run on anything that floats (with the exception of tiller handled small outboards on skiffs and then only due to space), has ALWAYS had an external filter.  Every wrench that I have ever known has always recommended the finest mesh filter for the application that the motor could support at about 1.5xmax fuel flow or more. The idea is that it is easier to change a filter underway then an injector or carburetor..  In the event of constant use of nasty fuel the recommendation was for a couple of filters in series going from course to fine mesh to try and keep stuff clean...

Bummer that folks that are paid to know sometimes don't, and don't know it....

[Capt Matt]

When I bought a 2000 135 opti mercury said not to run raycore on that motor too, by 2002 when i repowered I did it anyway it never seemed to be a problem on any of 5 opti's i owned.  Opti's also have a water seperator inside the cowling with a sensor that tells you if you have water in your fuel. Personally i love the clear bottom bowl of a raycore for the quick and easy view checking for water
Capt Matt

[daniel123]

Thanks for all the great advice, guys. Filter/Separator stays!

Dan