Fuel / Water separator for 3.0L Volvo I/O

[Craig W]

Hi All,
I've read through numerous search returns, and am begining understand the value of installing a fuel / water separating filter. I have a 98 4Winns Horizon QX with 3.0L VP/SX drive. My confusion is currently on "type" of installation. Sierra seems to provide a few options and I'd appreciate any feedback from any of you that can indulge me here.

-The inlet/outlet size for a suitable model, should be equal to that going to the fuel pump (I would expect..correct?)

-The higher the microns the finer the filter... but can too much be a bad thing? I'm wanting to separate just the water. The fuel pump has the ceramic element and theres the metal element in the carb. So a 10 micron would be adequate? I want to ensure that there will be enough flow as some of the units I've been searching rate on an engine being >200hp or <200hp rather than flow rated (which would be matched to a given application)

-The installation... I read a bunch about being higher than the tank to prevent syphoning. Should it be as close to inline elevation-wise with the pump as possible? (instead of the tank?) Pump is higher than the tank anyway.

what has caught my eye is the Sierra Kit w/Aluminum housing & Long Filter pt# 18-7775-1 (it expresses for Engine Type 200hp and above, 3/8" Inlet - which I still have to verify, but I think is what I have on my pump)

 

[robert graham]

Re: Fuel / Water separator for 3.0L Volvo I/O

Yep, that looks like it'll work fine, depending on your wide open throttle fuel flow,condition of your tank and fuel delivery system. If you have an older fuel tank with maybe rust, water, debris in it, then the filter could become plugged up fairly rapidly and restrict GPH fuel flow. You should always carry 1 or 2 aspare fuel filter canisters in your boat. I've used the Walmart Filter for several years now and have been just unscrewing it, dumping it in a clean container so I can get an idea of what trash/debris may be in my system, screw it back on and keep going. My motor-mounted under cowl filter is still there and is my second line of defense for debris in fuel, but since I added the fuel/water separater there's almost nothing at all in that one any more. I just bolted mine onto the inside of the transom, sort of out of the way, but still where I can get at it to change the cartridge. These filters are the best preventive maintenance items so far. Good Luck!

 

[Don S]

Re: Fuel / Water separator for 3.0L Volvo I/O

A 10 micron filter will filter smaller particles than a 30 micron filter will.

The outlet sizes on the the filter housing are in pipe thread sizes. A 1/4 or 3/8 pipe thread either one will work equally as well. What you need to look for is the hose barb size. There is where you want 3/8" hose.

If you use a 10 micron water seperating fuel filter, you will not have to worry about changing the filter in the pump in the future. The water seperating filter will do the job.

I read a bunch about being higher than the tank to prevent syphoning.

Doesn't make any difference, it will not siphon gas out of the tank or the pump. The gas comes into the filter from the top, therefore there is an air gap the gas can't get past to siphon. the tank also has an anti siphon valve.
All the posts about gas siphoning out of a carb are wrong, by design, it can't happen.

Mount the filter wherever you want, on the transom will work with no problem. Just make sure you can get to it to replace the filter yearly.

 

[Craig W]

Re: Fuel / Water separator for 3.0L Volvo I/O

Thanks Don & Robert. That helps. I agree, a spare canister is a good idea.

Robert, you mentioned "dumping" out the canister (into a clean container) does that actually work to release some of the debris? The canister looks similar to that of an oil filter and when I've flipped them over, on occassion to drain them, they really don't seem to dump out that easy... (but is that the difference between oil & water?! )

 

[Don S]

Re: Fuel / Water separator for 3.0L Volvo I/O

Robert, you mentioned "dumping" out the canister (into a clean container) does that actually work to release some of the debris? The canister looks similar to that of an oil filter and when I've flipped them over, on occassion to drain them, they really don't seem to dump out that easy... (but is that the difference between oil & water?! )

If you empty the contents out of a filter and reuse the filter, then you might as well not use a filter to begin with. When you turn it over to empty it, the debris and water from the "Dirty" side of the filter will contaminate the clean side.
The reason you empty it, is to see if there is water in the fuel. it will separate and you can see it in a clean container.
You then put a new element on.

 

[Craig W]

Re: Fuel / Water separator for 3.0L Volvo I/O

I personally wouldn't have thought of "re-using" the filter. For the $10-ish for a canister it doesn't make sense to dump and screw back on...I just didn't realize that anything would actually be released from the canister.