Fuel Filters and Water.

[Mark42]

How small a micron rating does a filter need before it filters out water? <br /><br />I see a filter that has a 10 micron and 250 micron media, just wondering if 10 is small enough to block the flow of water molicules.

 

[rickdb1boat]

Re: Fuel Filters and Water.

Hey Mark,<br /><br />I don't know if this will explain it all, but some interesting reading, nonetheless. I do know that the lower the micron rating, the better the filtration. And most filters sold have at least a 10 micron rating, which is excellent...<br /><br /> web page

 

[rodbolt]

Re: Fuel Filters and Water.

actually the filter does not filter out the water, the water seperates and settles at the bottom of the filter bowl. thats why some additives that emulsify the gas with water can pass through the filter and then the water will settle out in the fuel bowls.<br /> the biggest problem is usually the smaller the micron the less GPH it can flow and then it creates fuel boiling and starvation issues.<br /> most of the marine spin on filters will flow 90+ GPH and are 30 micron, yamaha came out this year with an element that will flow 90 GPH and is 10 micron.

 

[seahorse5]

Re: Fuel Filters and Water.

Several years ago Trailer Boats Magazine had a test of spin-on fuel filters, and tested them also for water retention. Even the 10 micron expensive Racor passed water thru it when the bowl filled up<br /><br />The new 10 micron Yamaha spin-on ($14) is supposed to be changed EVERY 50 hours. The smaller the microns, the quicker it plugs up.

 

[Mark42]

Re: Fuel Filters and Water.

Thanks rickdb1boat for the link. Good reading.<br /><br />So Rodbolt, you mean that the separation of water from fuel is not caused by the actual filter element, but just by the fact that water is heavier than gas and falls out in the relative calm of the filter bowl/housing? <br /><br />My main interest is ensuring that NO WATER gets in to the motor. <br /><br />I'll be installing a new one of these OEM style inlines:<br /> <br />

<br /><br />And would really like to get this Racor because it's see through :<br />

<br /><br />But what about these less expensive spin-on filters? They are half the price of the Racor above. How do you know when there is water in there? Just dump it periodically? <br />

<br /><br />How well do they perform compared to these $70 Racor units with water trap in bottom?<br /><br />

<br /><br /><br />EDIT:<br />OOps, Seahorse, I was typing when you posted. Interesting about the water passing when the bowl fills up. I think I would rather it clog and starve the motor.<br /><br />Anyway, thats why I like the top Racor, it has plenty of GPH for my motor, and a nice plastic bowl. But when I read Racor specs, it only holds 1/30th the material crud that the big boys hold. (1 gram vs 30 grams).<br /><br />But like I said, my main focus is keeping water out.

 

[rickdb1boat]

Re: Fuel Filters and Water.

I don't know, Mark. I use one of these and it seems to work fine. I just change the filter every year..<br /><br /><br />

 

[rodbolt]

Re: Fuel Filters and Water.

depends on if your actually gonna maintain it, and yes its a simple gravity seperation system the filter just filter particulates. that 26 dollar filter assy will work as well as that 70 dollar one it will just require replacing more often at about 6 dollars an element maybe less if you get them on sale. the racor you can drain periodically and extend the life a bit. that inline filter will trap no water, it will pass about 100% of it. <br /> if you really want to go high tech racor,yamaha and merc all make filters with water sensors that can be tied into your alarm system.<br /> and for those of you without enough toys onboard racor also makes a differential guage model with an alarm option that will tell you when the filter is clogging.<br /> but that little seachoice works ok. they rust quick in saltwater but if ya simply spin a new one on every 2 or 3 months its all good. that seachoce head can also be used with one model of the racor element and bowl assy, the new yamaha 10 micron, the napa gold element with a drain trap and mercs spin on as well as a few others. just make sure when you mount it you allow extra room below it for upgrades.

 

[Mark42]

Re: Fuel Filters and Water.

I don't even have water in my gas tank. I'm just parinoid about losing another powerhead like last summer. It looked like water damage, the rebuild shop said it was water damage, but I drained the carbs, fuel lines, and siphoned my gas tank dry and no water anywhere. I think water was coming from a head bolt that was all rusted when the others were not. But I want to prevent any possable water problems again. A few filters are a lot cheaper than another rebuild.