Mercruiser 3.0L Carb Fuel/Water Separator Install

Mordekai

Petty Officer 2nd Class
Joined
Jun 4, 2010
Messages
157
Has there been a guide written up on how to install a fuel/water separator for the ubiquitous 3.0L mercruise with the carb?

I'm looking to do mine as I'm starting to notice minor bogs already in a new engine and trying to keep the water/fuel with ethanol issues down to a minimum.

The only issue is I'm new to this and have no idea how to install one or what to get.

Thanks
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Mercruiser 3.0L Carb Fuel/Water Separator Install

If you have a Merc separator then it comes with instructions.

Bolt the unit securely to a bulkhead, usually in the engine bay, not too close to the exhaust system. Allow room to remove the filter when necessary. The separator has 4 ports, 2 in and 2 out. The kit also comes with 2 blanking plugs. On the top of the separator are 4 arrows, again 2 in and 2 out. Select the in and out ports most convenient and plug the other 2 ports. Screw the fuel line adaptors into the ports, connect the fuel lines and go boating....

Chris........
 

Rocky_Road

Lieutenant Commander
Joined
Oct 8, 2008
Messages
1,798
Re: Mercruiser 3.0L Carb Fuel/Water Separator Install

The thing that concern me the most is that kits like this do not come with extra fuel lines for the filter -> engine part and also line adapter since the connection to the separator seems to be threaded?

http://www.iboats.com/Fuel-Water-Se...4534554--**********.614238367--view_id.172310

Most kits include the threaded fuel line barbs, and on my 3.0L I just needed to cut the fuel line at my chosen location...no new line needed. You will need some marine grade hose clamps.

v680b9.jpg
 

Mordekai

Petty Officer 2nd Class
Joined
Jun 4, 2010
Messages
157
Re: Mercruiser 3.0L Carb Fuel/Water Separator Install

Most kits include the threaded fuel line barbs, and on my 3.0L I just needed to cut the fuel line at my chosen location...no new line needed. You will need some marine grade hose clamps.

Genius Idea, I'll see if I can splice in the fuel filter. Just to double check, the line that i'd want to cut in is the line that goes from fuel tank to engine right?

When I was looking, I see a black (pretty sturdy line) like the one in the pic above going to what it looks like a pump then out of that is a clear vinyl tubing into the engine.

So I'd be splicing in between fuel tank and fuel pump.. Am I correct on this?

Also do you have a link to your kit or which one would you recommend?

Thanks for the pic btw!
 

Rocky_Road

Lieutenant Commander
Joined
Oct 8, 2008
Messages
1,798
Re: Mercruiser 3.0L Carb Fuel/Water Separator Install

Genius Idea, I'll see if I can splice in the fuel filter. Just to double check, the line that i'd want to cut in is the line that goes from fuel tank to engine right?
Correct...the fuel ine that goes striaght to the fuel pump.


When I was looking, I see a black (pretty sturdy line) like the one in the pic above going to what it looks like a pump then out of that is a clear vinyl tubing into the engine. Also correct...that would be your fuel line. The clear hose going to the carb is to let you know when your fuel pump is leaking: fuel in the clear line, and you have a fuel pump leak.

So I'd be splicing in between fuel tank and fuel pump.. Am I correct on this? Always....

Also do you have a link to your kit or which one would you recommend? I used the Moeller (sp?)...but there are loads of good ones out there. What you are looking for is one that uses 3/8" barbs, instead of the 1/4". This gives your engine the volume that you want. I will link a great tutorial about these filters, which should answer any of you questions!


Thanks for the pic btw!

http://continuouswave.com/whaler/reference/fuelFilter.pdf

Happy boating!
 
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