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  1. #1

    Default 2006 BF90A - white smoke and water out exhaust

    I have twin honda 90HP engines and one has started smoking with white smoke and spurting water out the exhaust port above the water line.
    Motor seems to run fine at idle and WOT.

    Any ideas what could be the problem? Pic and video below....

    dropbox link to pic and video:
    https://www.dropbox.com/s/5kasj7nbz8...-6512.JPG?dl=0
    https://www.dropbox.com/s/29c5wlh0xt...-6513.MOV?dl=0

  2. #2

    Default Re: 2006 BF90A - white smoke and water out exhaust

    Based on reading other posts, maybe next is to pull the plugs and see what they look like, and possibly a compression test? How do you cut fuel on these carb motors - simply pull the fuel line itself into the motor (for a car I would pull a relay or fuse)? Will also IR temp the port and starboard engine next time and see if there is significant difference.
    Other thoughts?

  3. #3
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    Default Re: 2006 BF90A - white smoke and water out exhaust

    That "white smoke" i likely steam. The way it pulses in the video makes me GUESS possible head gasket failure at one cylinder.

    Pull the plugs and inspect for any that seem cleaner than the others. If you find one that stands out, that's your cylinder to inspect closely when the head is off.

    A compression test may confirm leakage but not always unless you can do it while the engine is in the state it's leaking IE: warm as opposed to cold.

    Good luck.

  4. #4
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    Default Re: 2006 BF90A - white smoke and water out exhaust

    Almost forgot...
    Yes, pull the fuel supply and idle the engine until it stops to shut off fuel.

    This would also be a good time to drain your carburetors.

    Good luck.

  5. #5

    Default Re: 2006 BF90A - white smoke and water out exhaust

    Ok - I did check the spark plugs and they look fine. Not wet at all, etc... Oil in dipstick looked fine as well - no water/milky anything. I did a compression test on all four cylinders and they were all about 125 so no differences. When I started the motor, my ir heat temp guage showed max up to 140 at idle. Also, steam doesn't seem to be coming out of that mid exhaust - just water. I see in another thread that this may be okay as it indicates some sort of blockage down through the prop, but not sure how to look at this. Is there something to do to flush out that exhaust side that might help? I usually flush after every use, alternating between salt-away and muffs and using the flushing port (for that I flush with fresh water for 10min). Any ideas? The starboard engine has zero water out the mid exhaust - so there is something definitely different. The PORT engine does stumble a bit at low idle and is a bit harder to start than the star board engine. What should my next course of action be? Thanks!

  6. #6
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    Default Re: 2006 BF90A - white smoke and water out exhaust

    Well, what jumps out at me is the compression. Depending on how you went about testing it, it seems pretty low for that engine. I would expect the compression on that engine to be well above 160 psi and possibly to 200 psi if it is "healthy".
    .

    Did you start with a fully charged battery that's in good condition? Did you remove ALL plugs for the test? Did you have the fuel delivery disabled? And, did you hold the throttle wide open when cranking?

    Doing those things will allow for the maximum measurable pressure the cylinders can produce when dry. Then, if the readings are low, you have the option to do a "wet" test to determine how well the rings are sealing.

    Comparing results to ones taken from the stbd. engine might give you an idea about how both engines are wearing.

    However, a cylinder leak down test will give you similar, reliable results.

    Good luck.

  7. #7

    Default Re: 2006 BF90A - white smoke and water out exhaust

    Agree - seems a little low. This was done cold. All plugs out, and the throttle in the cabin was set to all forward and put in neutral. I can compare next to SB engine, but it seems reasonable for a cold engine and one that I only cranked for 3-4 seconds.

    I probably should have done a test after I had it warmed up as well.

    The odd thing is still the water coming out of that high exhaust port. When I flushed the engine after running at dock for 20 minutes or so to check temps, no water comes out of that port at all.

    I just am not understanding the exhaust system. I am thinking the "steam" I see is only on cold days - so it really just the water sputtering out of that port, which is warm to hot. Is there some bypass valve that is not closing and diverting the flow to prop (ie letting some escape out that port)? Tell tale is strong.

    Could this be in any way related to thermostat opening some odd circuit? I wouldn't think so...

    Given the temps seem fine and engine seems strong, I have to think this is something related to the water exhaust circuit. What is a good way to get a shop/service manual for this specific engine?

    KRC

  8. #8
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    Default Re: 2006 BF90A - white smoke and water out exhaust


  9. #9
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    Default Re: 2006 BF90A - white smoke and water out exhaust

    Try the link above for a manual.
    I really don't know what might be going on with the exhaust. Maybe a cracked pipe causing the flow to be turbulent. Something like that or, as someone else suggested to you, possibly a blockage of some kind.

    Keep us/me posted as to how you're doing.

    Sorry I couldn't be of more help but not experienced with this model or outboard exhaust in general.

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