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carb problems ethanol fuel?-gctid387995

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    carb problems ethanol fuel?-gctid387995

    2007 bayliner discovery 192, 3.0 mercruiser. engine ran great until ethanol mixed fuel was used, engine would idle poorly or not at all and would cut out under hard acceleration & or die when quickly backing throttle off. removed carb, found some corrosion and rebuilt it since it was apart anyway. after rebuild removed all old fuel from tank & started with fresh pure off highway gasoline with no ethanol. old ethanol fuel had fuel stabilizer added to it. 1st time out on rebuilt carb, runs great, non of the previous problems occured. after checking the spark plugs does seem to run a bit on the rich side.

    has anyone else had problems with ethanol fuel or was it just a random carb problem. boat was new when i purchased it

    I have the same engine, just 11 years older and stickers everywhere to not use gasohol. As no one can get anything but E10 here since a long time the boat always was run on E10 and never had any trouble. Never used Stabil in it as the E10 already is filled with stabilizer to the top. Started this year with a tank full of gas around 1 year old and it just runs fine.

    My guess is that it was just a coincidence.


      Have never had a problem with my 5.0L OMC. The '87 manual says 10 percent ethanol is fine, so I am a little surprised that a '96 Mercruiser wasn't recommented to use ethanol.


        When I go again working on the boat next weekend I can take a picture of the sticker they planted close to the filler cap. It's naturally nonsense as everything after 1980 was ready for E10 and Mercruiser isn't an exception. Just a Bayliner specialty....... Have to find where my gas smell comes from.....


          I just replaced the fuel filters- one in the fuel pump and on is an in-line screen at the carb. I don't believe these were ever changed. The in-line screen looked like it had some congealed fuel in it. Definitely would be affecting fuel delivery. I have not been on the water yet, but with the muffs on at least, it seamed to start and idle much better. Also looks like it corrected a slight sputter when hitting the throttle. Very cheap and inexpensive maintenance.


            These threads can go on forever, and I hesitate to add to all the different experiences and opinions. Nevertheless, I want to comment from a somewhat different perspective.

            I have two carburated motorcycles on which I have spent thousands of dollars in the last three years on carb and fuel system work. I am strictly a recreational rider, so the bikes sometimes sit for months between rides.

            First, ethanol dissolves rubber, so all the old hoses need to be replaced with ethanol-tolerant parts. Same with o-rings and any other rubber parts in the fuel system. I had an o-ring on the petcock dissolve and hydrolock the engine on one bike, which was not a fun fix -- two years and three oil changes later, the crankcase still smells faintly of gas. Second, E-10 has a rather short shelf life, and quickly turns to goo in floats and carb passages. The most common problem with motorcycles is the smaller idle circuits in the carbs which clog very easily. Bikes won't idle, stumble badly below 3,000 rpm, and backfire on decel. The newer FI bikes don't seem to be affected as much, if at all. Maybe it's the high fuel pressure that comes with FI.

            I have found Seafoam helps, but is not the silver bullet; if you let E-10 sit long enough, even with a healthy dose of Seafoam, it will also degrade. An additive with Techron is helpful if you already have a problem and want to try to fix it without taking stuff apart.

            I've already replaced all the old rubber parts on my motorcycles and my boat with neoprene and ethanol-tolerant fittings, so the remaining problem for me is shelf life, and there's not much you can do about that other than try an additive. Fortunately, my marina sells non-ethanol 90 octane so I don't have to worry about it in the boat anymore. I also found a gas station about 8 miles from my house that sells 91 octane non-ethanol, which I am starting to use in the motorcycles and already use in the lawn equipment. Pricey, but worth it.

            So as E-10 applies to boats, it eats rubber and turns to goo if you let it sit for several months. If you have a carburated boat that sits for long periods, learn how to clean the carb. It's not really a matter of condensation, and a fuel filter won't help much if the E-10 that's in the float bowl and carb passages turns to goo.

            I won't get into the political reasons why ethanol sucks, such as subsidies, food prices, lower milage, etc.
            1996 Donzi 275 LXC
            7.4 Merc Bravo III
            Home Port Tarpon Springs, FL
            2002 Bayliner 1952 CN Cuddy
            Way Back When:
            1969 Slickcraft SS170 / 1971 Johnson 125