Merc 165 in line 6 - fuel filters

[David Foe]

I am amazed that my new to me 1973 Mercruiser has run happily for years without any fuel filters. On my sailboat's gas auxiliary engine I have a racor primary filter and an in-line polishing filter between the fuel pump and the carb.

Does anyone see a problem wirh installing a racor type filter upstream of the fuel pump and an inline filter downstream between the carb and pump. If so, is there a reasonable choice for the in-line filter?


Thanks! David

 

[ziggy]

Re: Merc 165 in line 6 - fuel filters

if your 165hp L6 is like mine, i suspect your do have fuel filters. one in the upside down bowl right on the fuel pump + one screen type right at the carb. inlet.

if ya wanna install a fuel/water separator i believe they go between the fuel tank and the fuel pump. ya want a solid line between the fuel pump and the carb.

 

[David Foe]

Re: Merc 165 in line 6 - fuel filters

Ziggy, you are right, I'm sure that I have those filters at the fuel pump and at the carb (I haven't yet found them myself but I will next time I'm at the boat) but since crud can block the carb jets it seems to me that a bit of fuel filtering/water separation would be a good preventative measure. I understand (and agree) that the line from pump to carb needs to be solid and that would make installing a "polishing" in-line filter more trouble than its worth. Still, aren't the pump and carb "filters" just a fairly coarse mesh screen? Given the grief that a plugged carb jet can deliver, filtering seems like a low cost measure.

Thanks!

 

[ziggy]

Re: Merc 165 in line 6 - fuel filters

hard to argue for not having a fuel/water separator. water in the fuel seems to be a common problem. especially with ethanol fuel.. which i try not to use.

myself, i've just never had any issues for needing any further filters than they came with from mercruiser.

when i got my boat i had some rusty's in my fuel tank too. enough to plug the fuel pump paper filter. more than once. i took my chance and ran through maybe 3 filters the first year i had it. 2 or three the next year and progressively less. i'm still on the same fuel filter i started with this year. i seem to have gotten away w/o removing and cleaning my fuel tank.

for my rig.
a paper filter on the fuel pump
fine mesh screen at the carb inlet

i do carry a spare fuel pump filter on board....