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Thread: Idle stall

  1. #1

    Default Idle stall

    My 2006, 20 horse, four stroke Honda outboard stalls when running in gear at an idle speed. The engine will run for maybe 8 to 12 minutes (give or take several) at idle when it will stall. Following the stall, with the engine in neutral, it fires right back up, and will either continue to run in idle or will easily take off. There is no hesitation in restarting. If running in idle after the restart, it may or may not stall again within the same time range.

    I assume this is an electrical issue, only because of the way it restarts. I would think it would be harder to start if it was running out gas, or there was any type of fuel issue. But, again, it starts immediately.

    I have taken it to a dealer, and they reported no issue. Possibly because when I said, it stalls at idle and they did not understand that I meant when in gear.

    I am thinking of selling the boat, but need to take care of this first Thanks for any ideas...

  2. #2
    Join Date
    Sep 2010
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    24,230

    Default Re: Idle stall

    Do you run fuel out of the carburetor when motor sits unused for say a few weeks ?------Small ports / passageways in carburetors gum up easily.

  3. #3

    Default Re: Idle stall

    Quote Originally Posted by racerone View Post
    Do you run fuel out of the carburetor when motor sits unused for say a few weeks ?------Small ports / passageways in carburetors gum up easily.



    I let the engine run out of gas, each time I bring it back in, so there is no fuel in the engine...

  4. #4
    Join Date
    Sep 2010
    Posts
    24,230

    Default Re: Idle stall

    Run with a timing light hooked up.----Monitor spark.-----See if it looses spark when it stalls ?

  5. #5

    Default Re: Idle stall

    Are you able to detect a smell of fuel when she stalls? It might be an occasional sticking carb needle valve not fully closing allowing engine to run rich enough to choke the engine, otherwise check the complete length of fuel line connections from engine to fuel tank pick up tube for possible air leak. I have known of an air bubble in the fuel line to cause a similar problem to yours at trolling speed. Over filled engine oil can also be suspect as excessive oil mist through the engine breather into the carb can interfere with the combustion process at idle speed.

  6. #6
    Join Date
    Nov 2009
    Location
    temecula, ca., usa
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    4,282

    Default Re: Idle stall

    Hi kyounger,

    Hmmm...
    Definitely an odd symptom. Because, as you say, it starts right back up.

    Is this remote or tiller? If tiller, pull only or electric start?

    Does the fuel line bulb remain firm when this happens? Like Milgrip says, it could be something with the fuel supply line or pickup or maybe even the fuel tank vent.

    Have you ever removed and drained the fuel chamber? Item 2 in the link below:

    https://www.boats.net/catalog/honda/...9999/fuel-pump

    The fuel chamber collects water over time and should be removed and drained of all liquid periodically to prevent it causing problems.

    If you can't find a fuel supply cause for this then, as racerone suggests, you will need to find out if it's losing spark during the occurance. Even with a timing light hooked up it might be hard to catch though.

    When was the last time you replaced the spark plugs? Sometimes a new set of NGK CR5EH-9 plugs can work wonders. I have a 2006 BF 20 D and have not experienced these symptoms..

    Get back to us about what you're finding and we will keep trying to think of things to try.

    Good luck.

  7. #7

    Default Re: Idle stall

    Quote Originally Posted by jgmo View Post
    Hi kyounger,

    Hmmm...
    Definitely an odd symptom. Because, as you say, it starts right back up.

    Is this remote or tiller? If tiller, pull only or electric start?

    Does the fuel line bulb remain firm when this happens? Like Milgrip says, it could be something with the fuel supply line or pickup or maybe even the fuel tank vent.

    Have you ever removed and drained the fuel chamber? Item 2 in the link below:

    https://www.boats.net/catalog/honda/...9999/fuel-pump

    The fuel chamber collects water over time and should be removed and drained of all liquid periodically to prevent it causing problems.

    If you can't find a fuel supply cause for this then, as racerone suggests, you will need to find out if it's losing spark during the occurance. Even with a timing light hooked up it might be hard to catch though.

    When was the last time you replaced the spark plugs? Sometimes a new set of NGK CR5EH-9 plugs can work wonders. I have a 2006 BF 20 D and have not experienced these symptoms..

    Get back to us about what you're finding and we will keep trying to think of things to try.

    Good luck.
    Thanks for the responses. I have a lot to check on. The engine was a tiller and I converted it to a remote. It acted this way while it was a tiller as well. I have had the carb off and apart several times, and based upon my limited knowledge, it looks fine. Most of the fuel line is new, but that doesn't mean it's not leaking air, so I'll check, along with the other suggestions. I had not considered the oil level - I assume it is fine, in that I have checked a while ago, but I'll check again. I am not sure about the fuel bulb, in that I haven't checked it, I just restart the engine. The plugs are fairly new, I would have to look at them to see if they are the ones listed above.

    Again, thanks much for the suggestions! I sincerely appreciate the help! kip

  8. #8
    Join Date
    Nov 2009
    Location
    temecula, ca., usa
    Posts
    4,282

    Default Re: Idle stall

    When you converted the controls did you verify that the oil pressure indicator and overheat alarm were hooked up and working? I ask because, at idle, the oil pump and waterpump are turning slowly. This results in lower oil pressure and less water being delivered for cooling.

    The engine CDI is designed to shut down the engine during overheat events.

    So I'm wondering about things like when was the last time thermostat was checked/ replaced? How long since the waterpump was serviced? Does she have a good pee stream at idle?

    Just some more thoughts about what might be happening.

    Good luck

  9. #9

    Default Re: Idle stall

    OK, so I checked out several items. The sparks were changed short time ago, and are the same number plugs mentioned above. They look fine, no heavy build up of oil or crud...

    I inspected the fuel hose connector to the engine. Interestingly, there is a small "square notch" on the inside black round plastic piece which rides against the chrome engine "receiver / connection." I don't see a purpose for this notch. It is not a crack or a broken piece missing, but looks like an intentional notch. I'll check on line to see if they with this notch new. All the fuel lines are new, except the ones inside the motor bonnet, starting on the back side of the same receiver which the hose connects to on the outside. There is also a small plastic old, fuel filter in this same hose, which leaves the connector and goes to the fuel pump. I installed a new inline fuel filter when replacing the original fuel line. Thus, I assume it would be fine to remove this filter and run on continuous fuel line from the connector to the fuel pump? I don't think it needs two filters. The new one I installed is in the fuel line, right before the fuel bulb.

    The oil level is fine...

    When I converted from tiller to remote, I simply removed the starter switch and safety cut off from the tiller arm and mounted them to the new console. The throttle of course now runs through the remote control. The oil light comes on when the engine is running. I changed the water pump recently also, thus the water flow is fine. I did not change out the water thermostat however. Yet, again, the engine doesn't over heat, there is no alarm going off when it stalls, and it starts and runs fine immediately.

    I have looked for broken or cracked wires and found none...

    I did not remove and inspect the fuel chamber for water issues, but I will.

    This is an odd issue that has been happening since I purchased the boat. So whatever the cause is, it has been there for while and has stuck around. It has to be something so stupid... in that when it stalls, it refires and runs fine. thanks again for the input and help. kip

  10. #10

    Default Re: Idle stall

    I forgot to mention, that is no o-ring inside the fuel line connector where the notch was found. Should there be? thanks

  11. #11
    Join Date
    Nov 2009
    Location
    temecula, ca., usa
    Posts
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    Default Re: Idle stall

    Welll Kip,
    You've done a lot and this is definitely a strange case. I can't check my fuel connector at the moment due to health issues but I will keep it in mind and liok at mine when I can.

    I do urge you to empty that fuel chamber.

    A couple of other things that come to mind that might contribute to this are idle rpm and carbonization.

    If the initial idle speed isn't set correctly, she might just be "on the edge" idling in gear. These twin engines like to idle at 900 rpm in neutral. They will run at a lower setting but the "droop" that occurs when placed in gear can cause stalling like this. If you have a means to check rpm you should give that a look.

    Or, just bump the idle up just a tad...say 50 rpm...and see if anything changes.

    The other thing is carbon in the combustion chamber. Lots of idling and trolling can lead to carbon buildup on the head and the valves. A "decarbonization" might help here. There's lots of ways to do a decarbon and my favorite is simply spritzing water into the intake at high rpm. It's actually a bit of a chore on this outboard because you have to pull the "muffler" (aka air intake housing) to do it properly.
    So you may want to do it chemically with one of the many product out there.

    I hope you get this figured out.
    Last edited by jgmo; 06-28-2022 at 02:49 PM.

  12. #12

    Default Re: Idle stall

    Removed the fuel chamber today, and found a small amount of water in the gas. Obviously, emptied it out, blew it clean and dry and put back on. Will test the motor when the threat of rain is gone... also thought I would take tools to adjust idle just case. Thanks for the help... kip

  13. #13

    Default Re: Idle stall

    Phillips screwdriver for the idle screw. Clockwise to increase

  14. #14

    Default Re: Idle stall

    Adjusting the idle is next. Waiting for cooler day to put it in the water... thanks - kip

  15. #15

    Default Re: Idle stall

    I took the boat out yesterday and it stalled while running at idle speed, even after cleaning out the fuel chamber, which did contain a small amount of gas. I then increased the idle adjustment maybe a quarter of a turn, and it seemed better. I same it "seemed' better, because it stalls after various time segments. So, yesterday after running a long while, there was not stalling. Next is to get a new tiny tach and see what the actual rpms are... thanks for the help-kip

  16. #16

    Default Re: Idle stall

    Stalling might be attributed to a bit of moisture remaining in the fuel system. Run some gas line antifreeze, Seafoam or similar product through it. Might help.

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