igneous
Active Member
Seen online that you should fill new w/f separator filter with gas before installing.....this true? Need pure gas go here:
http://pure-gas.org/
http://pure-gas.org/
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Water/fuel separator
- Thread starter igneous
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WAJetboating
Member
Absolutely untrue. In fact, when replacing both external filters (which you should do every fall during winterization), you should winterize the engine first... then disconnect and remove the battery... and only then replace the filters. This will leave them dry over the winter. As the good doctor pointed out, the (first, electric) fuel pump will fill them quite nicely.
To those who will claim filters shouldn't be left dry: That's how they come from the factory, and that's how they're stored for who knows how long on the shelf. As long as you are replacing with new filters, leave them dry.
itsabowtime2
Member
I disagree.
If you read the instruction on a Racor filter, it states fill with fuel before install.
http://www.parker.com/literature/Racor/21410_Rev_F_110A.pdf
If you read the instruction on a Racor filter, it states fill with fuel before install.
http://www.parker.com/literature/Racor/21410_Rev_F_110A.pdf
WAJetboating
Member
Are the Mercury filters made by Racor?
If so, do their generic instructions apply to the filters they make to Mercury's specifications?
And in any case, the normal reason for prefilling a filter (particularly oil filters) is to prevent them from being "pulsed" by the relatively high pressure oil pump. In contrast, the electric fuel pump on the SportJets is a relatively low pressure pump. It doesn't even run all the time - it only operates for ~20-30 seconds when you first turn on the key, specifically to prime the fuel system if any part of it is empty {ahem}. After that, the pulse-driven mechanical fuel pump on the side of the engine handles all low pressure fuel flow requirements.
Obviously, do what makes you feel best. As for me, I leave my fuel filters empty for the six months they sit in storage. That's how they sit in storage on the shelf until I buy them, and I doubt they "know" they're mounted on an engine instead of still sitting in a box. There's a reason Mercury tells you to run the injection system dry, drain the VST, etc.; it's not a good idea to leave even treated gasoline sitting in an engine for months at a time.
Finally, you can't really "fill" the inline filter anyway. When the engine, and thus the mechanical fuel pump, stops running the fuel in the line naturally drains back into the fuel tank due to gravity. Not sure how you're going to keep that filter "full".
Just my (and Mercury's) $0.02.
itsabowtime2
Member
If this is the type of filter being used, they recommend filling the filter.
http://bpi.ebasicpower.com/c/MER7E/Fuel+Filters+for+Mercruiser
All I am trying to do is state fact, not personal feeling.
http://bpi.ebasicpower.com/c/MER7E/Fuel+Filters+for+Mercruiser
All I am trying to do is state fact, not personal feeling.
WAJetboating
Member
For one thing, that's a canister filter. Not the same filter at all.
As I said, do what makes you feel best. My approach when I'm not certain about something is to call the experts. In this case, I called the Mercury factory and talked to the Mercury technicians who actually work on these engines. Their advice was as I've stated. They're also the ones who said to drain the VST - something that isn't documented anywhere in any Mercury manuals I've ever read. Nevertheless, the experts recommend it - so I do it. And I leave my fuel filters empty for the same reason.
igneous
Active Member
Well it's good to get different opinions on it. Not sure if Merc even states anything about it in manual and I happened to see a utube video where a guy was replacing on a larger boat that had an inline w/f separator in a compartment (not on engine). That's what made me wonder about it and I believe he was installing a Racor or similar since it had a visible plastic part on bottom w/petcock to remove water without removing whole filter. I do like that design if they made one for the SJ, but they're damn proud of 'em. I couldn't find a Racor that was replacement for merc 35-18458 anyway. Thanks for the link itsaboutime, do you have to replace mount or is it spin on replacement?
I got the Sierra 10 micron for ~$20 shipped ;^)
I got the Sierra 10 micron for ~$20 shipped ;^)
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WAJetboating
Member
The Mercury filter has a sensor on the bottom that unscrews to empty any accumulated water. It is not necessary to remove the entire filter. (For those that don't know, this filter looks exactly like a traditional auto oil filter and spins onto the engine in exactly the same way. It's mounted threads up, and the "cap" which is therefore pointed down has the sensor centered on it.)
Cost is ~$22, Mercury part number 35-18458Q4, available locally from most Merc shops since it's used on a wide variety of their outboard engines.
itsabowtime2
Member
All you need to do is just replace the filter.
I run the Racors on my Merc SBC's. When the day is done, the micron rating is what is most important (IMO). The more you filter out, the better (IMO).
I run the Racors on my Merc SBC's. When the day is done, the micron rating is what is most important (IMO). The more you filter out, the better (IMO).
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