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  1. #1

    Default BF40 light smoke after running WOT, carbs???

    Hey Guys, well after staying up late last night I was able to get my new 06 BF40 installed on my boat ready for it's first run this morning.
    Went great didn't miss a beat and besides a few pieces of shell blocking the telltale (giving me a very brief moment of anxiety) was basically faultless.
    However I did notice a couple times after coming back to idle from WOT there was a little bit of smoke coming from the exhaust.
    There was not alot of smoke and it certainly wasn't constant in fact if I stopped the engine and started again immediately it was gone, it only seemed to be present after dropping back from WOT sometimes. Back at home on ear muffs it ran for a good 15 minutes with no sign at all.

    As I've just bought this motor and it had been sitting for a couple months could this just be the carbs burning a bit of gunk that may have come loose running WOT?

    N.b. I also ran a compression test and got 115psi on all 3 cylinders, Pretty happy with that as I was on my own and unable to hold throttle all the way open from the control box.

  2. #2
    Join Date
    Sep 2008
    Location
    Hague, Virginia, USA
    Posts
    4,214

    Default Re: BF40 light smoke after running WOT, carbs???

    White smoke or black? Are you sure it was smoke and not steam? Any smell?
    CHawk 25 DLX

  3. #3

    Default Re: BF40 light smoke after running WOT, carbs???

    Quote Originally Posted by chawk_man View Post
    White smoke or black? Are you sure it was smoke and not steam? Any smell?
    It was white but quite possibly steam which makes me wonder if its not just a bit of water entering the exhaust and evaporatibg when backing off from wot, i might need to adjust the motor height on the transom. Can't say I noticed any smell at all
    Last edited by pseudonym; 02-22-2018 at 07:19 PM.

  4. #4
    Join Date
    Sep 2008
    Location
    Hague, Virginia, USA
    Posts
    4,214

    Default Re: BF40 light smoke after running WOT, carbs???

    I don't know much about the 40 hp Honda at all, but if steam I wouldn't worry about it. Just make sure that you are not overheating. If in doubt, get a cheap IR heat sensor gun and check heads after a good run. I think they are supposed to be around 160 degrees, but not entirely sure.
    CHawk 25 DLX

  5. #5
    Join Date
    Nov 2009
    Location
    temecula, ca., usa
    Posts
    2,907

    Default Re: BF40 light smoke after running WOT, carbs???

    Pull the plugs and see if any look MUCH cleaner than the others. If not, no need to be concerned about steam.

    Just wondering; when you performed the compression test, you say you couldn't hold the throttle wide open because you were alone. Most console remotes will stay wide open by themselves. Your's won't? Is it spring loaded to neutral?
    Just curious.

  6. #6

    Default Re: BF40 light smoke after running WOT, carbs???

    All plugs looked the same whe i did the compression test, took it out again yesterday, definitely nothing to be concerned about.
    As for the throttle on the remote it will stay full open however to do so the lever arm has to go into gear which then puts a physical lock on the ignition. I was using the idle throttle when i did the test but could see this only opened the throttle to about 2/3 WOT.

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