Need ideas for bad fuel

[AQUA222]

Did 35 miles in the "Morgan Joy" last week and she did almost perfect, burned 25 gallons running 3/4 throttle for half hour clips. But on the way in from about 10 miles out she started to hesitate.  My brother and I almost bit the windshield when she quit, out of the blue.  Started right back up and would run fine for 45 seconds then die again. Temp was good oil pressure was good so I suspected fuel, was acting like the float bowl wasn't filling fast enough. We could motor along just past idle.  Stopped one time to check the fuel filter at the carb ,470 mercruiser I/O, and it was full of junk. How does the inline water seperator filter, which was new that day, let particulates to the carb?  Also there is plenty of water in the fuel which was heavily treated in the fall, left tank full 85 gallons over the winter.  Need a little help, should I drain tank and start over? Should I carry extra spin on filters if I plan to go far? It is an aluminum tank that I cleaned and rebuilt 2 years ago so I am surprised to see anything by the way of dirt coming out if the filters.

[fitz73222]

Your fuel is so contaminated that the water separater is clogging up and the engine is starving for fuel, if it is bad enough, some of the junk will make it to the carb. Two choices, buy 3-4 more filters and keep changing them until you run out of fuel, or dump the fuel and start over.  If you are getting that much water in the fuel, try to figure out why starting with your overboard vent and see if its susceptible to getting water from spray down in it also check the Oring in your filler cap. Water is getting in there somehow.

[AQUA222]

Thanks! The vent is good. It is turned to the transom and high enough off the water line that I would be surprised if it even ever got wet. I have read mixed articles about storage if aluminum fuel tanks. I am in New England and the winter up here was harsh. I treat with e-sorb and stabil, if i use up the gel like you suggested, which I'm willing to do, will my problem continue? Should I leave tank full? Possibly spray foam the tank cavity to try to regulate the temp?

[Capt. Bob]

OK,

You stated you cleaned the existing tank. Was non ethanol fuel used in the tank prior to cleaning and are you using ethanol fuel now? If you used non ethanol before cleaning and non ethanol now you may be picking up residue from the cleaning that you didn't get completely out.

If you used non ethanol before and ethanol now, the ethanol has extended the cleaning process and is removing stuff you didn't get on the first pass.

Water in the fuel can come from a couple of places. If you are confident that you are not taking water on while underway, how good do you feel about your fuel source. Could it been contaminated when you refilled the tank?

Foaming in of a fuel tank is used for mounting purposes (I always thought) but remember what happens inside of the tank itself. Water vapor condenses on the inside surface of the aluminum when the inside surface temperature reaches the "dew point". Insulating (via the foam) should help keep the sides and end sections warmer but you don't usually foam the top or bottom. A thing to ponder is just how much water vapor is available to condense and over how long a time. Draining the tank (and burning the gas in a vehicle/lawn mower) is one approach.

In the future drain the tank each winter, add 5 -10 gallons in the spring and drain again. Again use in car/lawn mower. Start fresh each year. Even though I reside in Florida, I do this because my boat isn't used as much as I would like.

Good luck.

[AQUA222]

Thanks Cap! The second senario you described was my situation. Boat was land side for 7 years, maybe longer and the inside if the tank was slightly orange after I cleaned it, ironically the same color if the jelly I found in the carburator fuel filter.  Sounds like the new fuel is polishing the inside and giving me the issues. Thanks for the advise with the moisture, I have not thought about dewatering in the beginning of the season. I'll try it and let you know how I make out.

[AQUA222]

Well.... We are at it again....changed the fuel water separator filter, poured fuel into glass container to see what was in it and it was clean.  Cleaned carb filter again and tried running motor. Took a bit to start while fuel was pulled through the new filter then it fired right up, wiggled a little like they do when cold.....and died. Would not start again after that, is acting a little like timing, like it wants to start but won't quite fire. Plugs are good, wires are new, did not check points yet, is it possible the timing got off from my 35 miler? Aaron.... I guess it's time for the pertronix , installed it last season and it ran worse, so I put the pions back in it.

[AQUA222]

Fuel pump .....

[AQUA222]

Trying not to bore with my..."engine woes" as the title of this thread suggests...but, ordered new fuel pump and was as excited as a kid on Christmas when it came in and while threading in the new fuel fittings, snapped the cast aluminum case.... Was able to Frankenstein with pieces from the old pump and figured I was on my way. Launched yesterday by myself with plans to pick up the family on mother in laws dock, ran perfect from launch to dock, about 2 miles at 7 mph picked up family, motored up the river to non wake zone and opened her up, ran great about 5 minutes 3/4 throttle then quit out. Started right back up and back to drop off family and scratch my head. Feels like still not getting fuel and high rpm. Tested fuel pump in driveway, took fuel line off carb into a glass jar and started the boat with what was in the carb.  Started and ran, fuel pumping into jar. Fuel is clean no evidence of water or particulates and smells like fresh gas. I'm stumped?!