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Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10904
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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I suspect a blockage in the cooling system. New water

Customer Question

I suspect a blockage in the cooling system. New water impeller(probably not needed) With the thermostat removed, inserting a hose in the cavity shows no cooling indication at the indication on the starboard side of the motor.
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else the Marine Mechanic should be aware of?
Customer: none that I am aware of.
Submitted: 10 months ago.
Category: Boat
Expert:  Tan replied 10 months ago.

Hello. My name is Tan.

Could I get the make, model and serial number of your engine please?

Customer: replied 10 months ago.
Honda BF40A BAYS(###) ###-####
Customer: replied 10 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Provide Diagrams, Manuals, or Instructions. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Tan replied 10 months ago.

Is the engine over heating? Did you try leaving the thermostat cover off and running the engine do you get water out the opening in the block?

Customer: replied 10 months ago.
I haven't tried that.
Customer: replied 10 months ago.
The engine does not overeat
Customer: replied 10 months ago.
I will run the engine in a few monutes
Expert:  Tan replied 10 months ago.

If engine doesn't over heat then you don't have blockage. What makes you think there is an issue. The engine doesn't always pump water out both ports at the rear of the engine.

Customer: replied 10 months ago.
shouldn't there be flow from the water indication on the starboard side?
Expert:  Tan replied 10 months ago.

If you are referring to the tell tale yes. Have you tried clearing the tell tale with a small piece of wire with engine running on flush attachment? The tell tale can get plugged with debris and stop pumping.

Customer: replied 10 months ago.
I will try that. It will take me a few minutes.
Expert:  Tan replied 10 months ago.

Ok take as much time as you need I will will be here.

Customer: replied 10 months ago.
Engine won't start. I will get back to this when I solve that problem.
Expert:  Tan replied 10 months ago.


Customer: replied 10 months ago.
Solved run problem. Water comes out of thermostat cover, still no water from telltale drain.
Customer: replied 10 months ago.
I did run weedeater string in the telltale. It went in about 5 inches.
Expert:  Tan replied 10 months ago.

Ok follow the telltale from where it exits the motor to where it connects to the motor. Pull the hose off at the motor and start engine stick wire in the fitting to clear fitting. Does it pump water out the engine where the tell tale hose connects to the engine?

Expert:  Tan replied 10 months ago.

Here is a diagram of the fitting # 9 and where it is in the block. Pull hose off this fitting in the block start engine with wire clear the fitting.

Customer: replied 10 months ago.
OK! Finally got flow out of the telltale drain. My owners manual shows it incorrectly. Thank you for your help.Bob
Expert:  Tan replied 10 months ago.

Your welcome Bob. Please don't forget to positively rate my help as that is the only way I get credit for helping you. To rate click on the stars at the top of the page 3 or more please.

Thank you.........Tan

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