Author Topic: Checking fuel filter  (Read 2780 times)

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Offline Plugcheck

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Checking fuel filter
« on: June 17, 2018, 12:10:54 PM »
My new merc fuel filter/water separator came in, so I thought I'd take a moment to inspect what comes out, or rather what the filter has stopped.  A rather nasty cocktail of crud, water, and gas.   I change these every year, so I'm surprised how much gunk came out from one season.  Just a guess, but the fuel in the belly stays cold, outside moist air then condenses into the fuel?  Tanks are open vented to the atmosphere, so I suppose that sounds plausible.
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude

Offline thedeuceman

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Re: Checking fuel filter
« Reply #1 on: June 17, 2018, 12:23:33 PM »
Wow, that’s a lot of water. When I was dealing with my fuel pump issue a couple weeks ago I checked The filter. Clean gas and no water. But one time last season it quit running and it ended up being the filter full of water that was causing me trouble. I attributed that to the same situation.
Although, in contrast I have a filter with a plastic bowl on our GT, three years, I have never seen water in it.


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Joe
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Offline Rich_V174SS

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Re: Checking fuel filter
« Reply #2 on: June 17, 2018, 10:16:51 PM »
Check to make sure your filler cap has a good seal or O-ring around it or else rain water can get in that way too. If your tank is aluminum and below the deck it could have holes rotted through the top or sides where water can get in. There's often a tell-tale odor that smells like a combination of gas, ammonia and vinegar that accompanies tanks with rot. I know because I replace several tanks each year when I'm working at the boat shop.
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115

Offline Plugcheck

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Re: Checking fuel filter
« Reply #3 on: June 18, 2018, 09:14:41 AM »
     The tank was cleaned, blasted, and repaired before it was reinstalled back when I did the CVZ resto.   I had one area that I had to cut out and weld in new, it was just pitted and soft.  It happened in an area where the foam got saturated and was in contact with the side of the tank.   Fortunately the inside looked better than the outside, I used a sewer inspection camera to give it a good look around.   The amount of water I collected from the filter seemed to be  plenty, but I also ran through probably 200 gallons of fuel last season, 70-80 was at Red Wing meet alone.   So as a percentage its not very high of water to fuel, I was just concerned where does it come from.   The filler is new and the ring is in place and pliable.    Could spray get in the vents, there are two on the Z?  Could come from the gas station?  Marinas probably have better quality fuel, but I generally fill at the local gas station. 
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude

Offline Rich_V174SS

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Re: Checking fuel filter
« Reply #4 on: June 19, 2018, 06:42:04 AM »
Automotive gas stations are usually pretty good because they have faster turnover, and if they did have water in the tanks there's gonna be someone with a broken down car complaining. I find a lot of people get water in their outboard portable cans when they bring in their small engines with water in the carbs.

If you continue getting considerable amounts of water in your filter I'd be looking for more holes in the tank. They can pop up quickly once the corrosion starts.
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115

Offline Plugcheck

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Re: Checking fuel filter
« Reply #5 on: June 19, 2018, 07:21:47 AM »
I will pull the filter and drain this fall when I winterize to check.  Unlike Doran, I really don't have access to the belly tank after the resto, so it would be a major surgery to perform.  No leaks at this point, so that is a good sign. 
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude