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BF9.9: Water out Exhaust Idle

J

jhock

New member
I searched this forum and did not find an exact answer for this issue. Upon launch this year my BF9.9 (approx. 2000) did not have much flow through the cooling water indicator. Upon further inspection, I notice that water was instead coming out of the idle exhaust port. I cleaned the indicator outlet with some wire and it is now coming out in a steady stream (quite forcefully at full throttle).

However, water is still spitting out of the idle exhaust port at higher RPMs. I let it idle for a long time (it did not overheat) and upon throttling up there was just a small amount of bluish smoke out the idle exhaust. However, within 15 seconds, it was again spitting some water out. I can see that at full throttle exhaust is exiting the main port underwater (bubbles shooting out of prop), so it is not (completely) plugged.

My question is: Did I break something when I briefly ran it with the indicator outlet plugged? Did water force itself around some seal and permanently damage part of the plumbing? At first I was worried about water getting into the combustion chambers, but there is no difference in engine operation. Also, after running for quite some time I immediately checked the oil and it was not milky or foamy. I find the parts diagrams do not give me enough detail to follow the exhaust/cooling water path to make an educated guess on my own.
 
I don't think you have any reason to worry. Water comes out of that port, from time to time, on all the small Hondas I've worked on so I consider what you are describing as normal. Water is supposed to come out the exhaust and that is part of the exhaust.

Although, like you, I wish Honda had done a better job of explaining the coolant passage routing and strategy instead of assuming we're all born with the knowledge.
 
Thanks so much, I made a forum bad and posted this same topic twice. I would delete one, but perhaps only the moderator can do that.

Either way, it is reassuring to get the same advice from two different people and I appreciate the feedback. The motor is a bit oversized for my 22ft sailboat, it pushes me 3 knots at idle (hull speed is 6.5). I've never really paid much attention to the backside of the motor while it is at higher RPMs since I'm usually looking at what is coming once I've shifted out of neutral.

Systems rather than parts diagrams would be helpful, but if those exist, they are probably only available to certified mechanics.
 
Well, there is a very good shop manual available but it wouldn't have been of much help in this case. That is, unless they've updated it recently. I have manuals for a few different models and none of them explains the cooling system very thoroughly. The exhaust bypass doesn't get much of a mention at all as I recall but, then, that's why we hang out here. To share knowledge and offer support to one another when we can.

Welcome aboard the forum and
Happy sailing.
 
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