Water Separator or Fuel filter?

**Bullet 20cc** · 10-07-2017, 03:20 PM

Originally Posted by ghost28

Mercury issued that bulletin like 20 years ago...lol...alot has changed...you run what you like but when **** gets in an opti fuel system it aint cheap to fix...

This is the perfect reply for any direct injected outboard...or any fuel injected outboard (2 or 4 stroke) if you don't like having pricey fuel system problems. Much easier and cost effective to spin on a filter every 250 hours than paying your mechanic. $75 for filter/water separator system and less than half that for 2 minute filter changes and expensive fuel system problems just don't happen anymore.

**2.5-21** · 10-08-2017, 02:47 PM

George, Do you run 5/16" fuel line or 3/8" up to the Vacuum pump for a VST motor?

**Bullet 20cc** · 10-08-2017, 02:53 PM

I can't speak for George but 3/8 all the way to the LP's on V6's. You would be fine with 5/16 on V4 and below.

**2.5-21** · 10-08-2017, 03:00 PM

Originally Posted by Bullet 20cc

I can't speak for George but 3/8 all the way to the LP's on V6's. You would be fine with 5/16 on V4 and below.

Mercury ships the new motors with a low pressure pump 5/16" nipple and a molded 5/16" hose down to the rigging tube to connect to what ever you bring to it.

**Bullet 20cc** · 10-08-2017, 03:35 PM

Originally Posted by 2.5-21

Mercury ships the new motors with a low pressure pump 5/16" nipple and a molded 5/16" hose down to the rigging tube to connect to what ever you bring to it.

100% true on stock Mercury motors...but 3/8 fittings on stock big boy (V6) Yamahas. Why does Mercury go small and Yamaha goes big? Fuel starvation is not something to be chanced on high rpm outboards...especially 2 strokes. Fuel starvation at higher rpm's = lean conditions and a very expensive POP! How much does 3/8 fittings and fuel line cost? Very inexpensive insurance...but with anything to each their own.

**NICE PAIR** · 10-10-2017, 07:55 AM

I'm running 3/8 on my XS's but I gotta ask ... How can a motor that uses 1/2 the fuel my old 300 Pro Max burned need anything bigger than Mercurys supplied 5/16 pigtail.

I used to run pre-filters ... did not with my new XS's. I have new tanks and am going to look @ the vst filters @ the end of the year (100/110 hrs.) All that I see @ risk with normal maintenance is the transfer pump.

All I found in my pre-filters in the past (old tanks) was fiberglass when they finally came un-glued. (450 hrs.)

my $ .02 :-)

**2.5-21** · 10-10-2017, 07:57 AM

300X (fuel disposal plant) comes with same 5/16" fuel hose and low pressure pump

**ghost28** · 10-10-2017, 12:50 PM

I run 3/8 line on everything...I have seen 3.o liter mercs and yamahas have issues with 5/16 line...if the runs were really short with limited bends and fittings and whatnot you could probably get away with 5/16 but i aint taking a chance....

**Bullet 20cc** · 10-10-2017, 01:19 PM

All good questions for Brunswick (before 2014) to answer about those Mercury motors. Also why did they start making plastic bowling pins when their wooden pins sounded better? Also are their billiard balls still made of ivory or are they using synthetic materials since elephants are more protected now?

The Yamaha guys are busy engineering exhaust systems for ridiculously expensive supercars like the Lexus LFA in addition to producing superbikes, banshees, dirt bikes, snowmobiles, waverunners and lots of precision musical instruments (I play their drums). And for some reason those engineering masters of the universe put a 3/8 nipple on their 250's...go figure.

**Bullet 20cc** · 10-10-2017, 01:25 PM

Originally Posted by ghost28

I run 3/8 line on everything...I have seen 3.o liter mercs and yamahas have issues with 5/16 line...if the runs were really short with limited bends and fittings and whatnot you could probably get away with 5/16 but i aint taking a chance....

This post is it...

**2.5-21** · 10-14-2017, 10:12 PM

So after many years of rigging boats and using a mercury water separator religiously (some using a racor spin on with a clear bowl) but mostly just a steel can.
I began to research a better way to filter todays alcohol infused fuel and found this Racor fuel filter with a built in Primer pump.
Using this will eliminate the use of todays crappy primer bulbs as well.

The mercury filter is rated around 60 GPH when using a racor element and only has 1/4" npt fittings , This Racor filter is capable of 90 GPH and has full 3/8" npt fittings.

you could almost rig 2 engines off this one filter (not that I would) the cost is almost the same for the Racor vs. the mercury plus the cost of a primer bulb.

**XstreamVking** · 10-15-2017, 03:10 PM

I gave up on the plastic bowl racors. The alcohol kept eating the plastic and when you gave the primer a pump the bowl would blow off. I am not kidding! I went to the wix filters that are all metal.

**Bullet 20cc** · 10-15-2017, 05:25 PM

Are you serious!? I have run the plastic bowls for as long as I can remember...probably since they came out. The fuel pump here gives 10% ethanol (probably 10% horse urine too) and never even had a leak. I do put a new filter and bowl on at the same time when I change but that's not til every season...about 200 hours give or take. Kinda scares me a little now...that's bigtime fire hazard! Not cool...

Anybody else ever had that happen?

**2.5-21** · 10-15-2017, 05:42 PM

The new Bowls are alcohol compliant, I have seen some of the early ones turn to goo but those were made before the govt. started using liquor for fuel additive!
Be careful buying new old stock on ebay you may get one that will dissolve.

**Bullet 20cc** · 10-15-2017, 05:48 PM

Originally Posted by 2.5-21

The new Bowls are alcohol compliant, I have seen some of the early ones turn to goo but those were made before the govt. started using liquor for fuel additive!
Be careful buying new old stock on ebay you may get one that will dissolve.

Ugh...ebay is where I always get them too. Ok I feel a little better now...will be paying attention to that in the future. Much appreciated!