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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16118
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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I have a honda outboard 2003 bf 50 and i noticed yesterday

Customer Question

i have a honda outboard 2003 bf 50 and i noticed yesterday that the water from the exhaust in coming black
JA: Sometimes boat issues seem like they'll be really complicated, but end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: i have the engine out of the sea now and from the water extraction i can see black water coming out
JA: Is there anything else important you think the Marine Mechanic should know?
Customer: when i leave the engine on neutral running as normal after 5-6 minutes the revs increase and then it goes back to normal. is tha t normal?
Submitted: 1 year ago.
Category: Boat
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Jason replied 1 year ago.

Hello my name is ***** ***** am I speaking with?

The engine needs to be compression tested, is that something you can do?

Customer: replied 1 year ago.
is that for sure? it sounds and runs very good. what compression am i looking for?
Customer: replied 1 year ago.
what is that black water and what do you thing is creating that?
Expert:  Jason replied 1 year ago.

I think the engine has low compression, it would fit the symptoms of black exhaust water. Can you do a compression test and get back to me with your results?

Customer: replied 1 year ago.
the motor is in corfu and i am going there tomorrow night
i will do the compression test when get there and get back to you thursday morning.
thank you Jason
Expert:  Jason replied 1 year ago.

You are very welcome. Post back with your results and we can take it from there.


Customer: replied 1 year ago.
Hi Jason
I did the compretion tests and it comes out
Cylinder 1 210 psi
Cylinder 2 209 psi
Cylinder 3 210 psi
I noticed that my new spark plugs are black when I got them out
What shall I look for next?
Expert:  Jason replied 1 year ago.

Got it. If you run the engine, does the engine actually heat up? Run the engine for a bit and then touch the tops of the cylinder heads and let me know if it's getting hot or not.

Customer: replied 1 year ago.
Thanks Jason
All temperature is normall and runs very well. All I can think is that a lot of petrol flads the motor and doesn't burn properly .
Expert:  Jason replied 1 year ago.

A 2003 BF50 should be a carbureted engine. Just to make sure, is your engine carbureted or EFI?

Customer: replied 1 year ago.
Good morning
Yes there is 3 carbs and I used the carb tuner and is all balanced ok.
Expert:  Jason replied 1 year ago.

Hi Chris,

How does the engine otherwise run? Does it idle correctly, accelerate well, and make full power under load?

Customer: replied 1 year ago.
HI Jason
The engine runs very well, very quiet and idle is correct. Under load today tested to a 7 mile distance and went very well and healthy . Acceleration is very good
Expert:  Jason replied 1 year ago.

No more black water?

Expert:  Jason replied 1 year ago.