Water Separating filter? 1987 3.0 GM Mercruiser

[Starcraft5834]

Ive got a 3.0, was thinking of installing a water/fuel separation filter next spring... I've seen a few vids on installation and placement on fiberglass/wall of engine hole...looks pretty straight forward.. anyone had any problems after installing one? ie- fuel pressure issues? to carb... or should I be good to go? thanks all..

 

[BigDog98]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

Ive got a 3.0, was thinking of installing a water/fuel separation filter next spring... I've seen a few vids on installation and placement on fiberglass/wall of engine hole...looks pretty straight forward.. anyone had any problems after installing one? ie- fuel pressure issues? to carb... or should I be good to go? thanks all..

You should be good to go. But do you have a electric fuel pump or a manual fuel pump meaning it only turns on when the engine cranks over and the oil pressure goes up? Which one is yours? And i would defiantly recommend putting on a fuel/water separator system in your boat. I change mine out every year and every year the filter is filled all the way to the top with water because of this ethanol based fuel!

 

[Fishermark]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

Yes put one in - put it between the tank and the pump. I made a bracket to install it on the side of the engine... but if you have access to the transom area, that works too. If you do not mount it to the engine, be sure to use type A1 marine fuel line between the filter and the pump. (You do not want a hard metal line as it needs to flex).

 

[Fishermark]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

I change mine out every year and every year the filter is filled all the way to the top with water because of this ethanol based fuel!

If your separator is full every year, I would suspect you are simply getting water in your tank - not a case of ethanol fuel absorbing water. It is something that you ought to check at least in order to rule it out.

 

[BigDog98]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

If your separator is full every year, I would suspect you are simply getting water in your tank - not a case of ethanol fuel absorbing water. It is something that you ought to check at least in order to rule it out.

No i am sure that its not. Every year i get the tank pumped out for inspection and every year it has water inside. I have replaces all hoses before and the fuel cap and still gets water. I have a 70 Gallon tank and fill it up almost half way before going out and the left over fuel sits there for a while. I had people come before with a test strip and check what is causing it and they said that its the fuel because i get my fuel from a regular gas station and never marine fuel. They told me its was the percentage of ethanol in the fuel causing it. ! But now for the past 4 month i was using marine fuel and i did not have any problems anymore!

 

[Starcraft5834]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

manual fuel pump.. I've got a bunch of room "in the engine hole", fiberglass wall,, on fuel line side.. I should probably replace entire lenght of fuel line from tank to engine? my fuel line is original.. no leaks, but old.... figured since I was going to cut it anyway to do this might as well be new..

 

[BigDog98]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

manual fuel pump.. I've got a bunch of room "in the engine hole", fiberglass wall,, on fuel line side.. I should probably replace entire lenght of fuel line from tank to engine? my fuel line is original.. no leaks, but old.... figured since I was going to cut it anyway to do this might as well be new..

Yea good idea. Always start from new parts when starting a project that involves them. And i would also consider upgrading to a electric fuel pump. I dont know why that just me. I guess the electric ones are more reliable!

 

[achris]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

If you change to an electric fuel pump (and I don't necessarily consider it an upgrade), you absolutely MUST put in the appropriate oil pressure switch to ensure the safe operation of the pump... ie, pump stops running if the oil pressure is lost (engine stalls)...

OP, when you put the fittings in the filter housing (for the fuel lines) make sure you don't over-tighten them. If they are over-tightened they crack the housing (just a tiny hairline crack you can't see), then the system sucks air in the fuel and you get all sorts of 'running out of fuel' type of problems... And use Loctite 567 on the threads, not thread tape!!!

Chris.......

 

[Starcraft5834]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

gonna keep the manual one Chris.... gonna try not hurting myself tackling this little job . had issues with carb this past season,, got it running good now, thought getting rid of moisture would keep the old girl happy.........this boating thing has been a blast thus far,, expensive one, but worth every penny.. cant put a price on quality of life......I've certainly had lots of good times in year 1 with my purchase so far.. family/friends,,, watching friends crash on tube/ski's, watching my son scuba dive in crystal clear water on one of NYS Finger Lakes,, it's awsome!! I've cursed and banged my head a few times too!! that's what boating is........thanks all....

 

[BigDog98]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

gonna keep the manual one Chris.... gonna try not hurting myself tackling this little job . had issues with carb this past season,, got it running good now, thought getting rid of moisture would keep the old girl happy.........this boating thing has been a blast thus far,, expensive one, but worth every penny.. cant put a price on quality of life......I've certainly had lots of good times in year 1 with my purchase so far.. family/friends,,, watching friends crash on tube/ski's, watching my son scuba dive in crystal clear water on one of NYS Finger Lakes,, it's awsome!! I've cursed and banged my head a few times too!! that's what boating is........thanks all....

Good luck !

 

[superbenk]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

Agree with Fishermark, you shouldn't have a filter full of water every year. I don't think I've found water in my gas yet & I always fill up with E10 at the gas station on the way to the lake. Sounds like something else is wrong. Maybe your vent is missing the up turn loop in the line & letting water splash in.

As for adding the filter it's super easy & I'd recommend using 10 micron filters over the typical 25 micron for added security. They still provide ~90GPH flow which is plenty for a 3.0L.

 

[Starcraft5834]

Re: Water Separating filter? 1987 3.0 GM Mercruiser

thanks all..