Is it OK to Switch to a 2 Micron Fuel Filter?

[HMBJack]

In the interest of keeping my VST clean, is there any downside to switching from the big blue Yamaha 10 micron fuel filter/water seperator to a 2 micron one?

I run twin 2006 F250 TXR's. I read that Rodbolt doesn't like the 2 micron set up.

Thanks,
Jack

[boscoe99]

I actually used a two micron filter. First with my Merc EFI and then with my Yam F200. No problems whatsoever.

Not speaking for rodnut but I believe that his concern was that it might be overly restrictive to fuel flow. Which is a valid concern. If the fuel is particularly dirty then the filter may clog sooner than would the ten micron filter. But if I have dirty fuel that is exactly why I would want a two micron. To keep debris from getting to the motor.

To allay any concerns about excessive restrictions to fuel flow I installed a vacuum gauge in my fuel delivery system. I could just take a glance at it from time to time and see that all was well. Another bonus of having the gauge was that I did not prematurely remove and replace the filter. I could see if and when it go dirty enough to be need replacing. Might have been three years or so.

[DennisG01]

I think in an "ideal" world, you would install the 10mic first, then the 2mic. That would give you the protection of the 2mic but also add longevity to filter life and decrease the chances that things clog up when you're 20 miles offshore. With you're Grady, you certainly have room to install it. But the other side of this is initial cost - another filter head and filter and some gas line. Options, options, options!

I did the same vac gauge install that Boscoe did about 6 years... with his help! FYI, I haven't changed that filter, yet! Or maybe I did once "just because"? I don't recall.

https://www.yamahaoutboardparts.com/...stall-question

[boscoe99]

My Racors would be removed for rust long before they got too clogged.

[HMBJack]

Thank you for your remarks and feedback. Very helpful...

As stated, I'd rather have a clogged Racor than a clogged VST

[Ferris11]

Boscoe, what type and brand vacuum gauge did you install that gave you a better resolution scale? I've been using a 2 micron racor filter on my 2006 f90 motor after reading some past posts of yours. All of the vacuum gauges that I have looked at have a range of 0 to 30 hg which does make harder to find a small restriction and so I have resorted to change out the filter every 2 years just in case.

[DennisG01]

Boscoe, what type and brand vacuum gauge did you install that gave you a better resolution scale? I've been using a 2 micron racor filter on my 2006 f90 motor after reading some past posts of yours. All of the vacuum gauges that I have looked at have a range of 0 to 30 hg which does make harder to find a small restriction and so I have resorted to change out the filter every 2 years just in case.

FYI, while Boscoe makes a vaild point on the scale, it is still plenty easy to see 1 PSI of difference on the 30PSI gauge I have.

[oldmako69]

Thank you for your remarks and feedback. Very helpful...

As stated, I'd rather have a clogged Racor than a clogged VST

I posted this recently on THT. It depends on what the VST is being clogged with. I had constant fuel problems with my F225s. My Racors were never the problem and always spotless. The problems were downstream. Just my experience and opinion, FWIW....

"It's worth repeating, ethanol destroys the fuel lines downstream from the HP pump inside the VST. These are the small High PSI lines that carry HP fuel to the injectors. These lines supply more fuel to the injectors than they can use. The excess fuel is returned to the VST in the fuel "loop". That excess fuel also brings back to the VST all of the crud which the E10 sloughed off on the inside of the fuel lines. All of this is downstream of your add-on filters. I never had problems with my upstream Racor. Never. It was always the screen on the HP pump and the injectors themselves. They were constantly loaded with tiny bits of rubber. The large bits would accumulate on the upstream side of the screen. The medium-sized ones would kill the pump, the tiniest bits would foul the injectors.

So, you CAN remove that screen/filter from the bottom of the HP pump, but you won't fix all of the problems with this engine's fuel supply. The HP pump will clog with this crap. The injectors will clog with this crap. Been there, done that a bunch with my 2005 F225s.

On my engines, I replaced all the fuel lines downstream from the tanks and the engines themselves. Those little fuel lines on the V6 are stupid money. Like 800 bucks per engine and many are no longer available. I just used the best quality HP fuel line I could find online and saved 750 bucks. But, you'll need to get creative running several of them since they have sharp bends. Add loops and length to get what you need. Or, send Yam 800 bucks per."

[HMBJack]

Thanks Old Mako.

I have been buying my fuel from one place (my local Fuel Dock) for 12 years. No effects of ethanol on the interior of my F250's yet (2,470 hours and counting).

Either my fuel source is good or my fuel lines are resistant to ethanol, but I have yet to experience issues in my VST's as you have with your F225's.

I really like your suggestion to change out the fuel lines since they are downstream of the Racor tank filter. Thanks!