2000 Yamaha 15 HP Cooling issue

[2mdsailors]

Hey Guys,

I've search through past posts and nothing quite fits what has happened to the cooling water output of my motor.

The '00 F15 is on my 34' Trimaran sailboat and this past week in the cooling water output will stop if the motor in its normal height. I get cooling water flow if I lower the motor to the lowest position of the my Garlick adjustable mount.

At idle the flow is fine in normal and low positions. Once I open the throttle the flow stops in normal position, but is fine in the low.

The lower unit seems to have a lot of air bubbles coming out just above the plate on just the right side (facing forward)

We keep the boat on a mooring, so getting the motor off is not the easiest to do, I need to transfer to my inflatable to put up on a dock.

I was able to get the cover off of the thermostat and did have some slight salt crystal built up.

Any guesses?

 

[99yam40]

Re: 2000 Yamaha 15 HP Cooling issue

when was the last time you changed the water pump?
They are normal part of the maintenance of the outboards.
Do you flush the salt out after running in salt water?
If not you could have salt and corrosion in the passages blocking flow.

 

[2mdsailors]

Re: 2000 Yamaha 15 HP Cooling issue

Thanks 99yam40,

This starts my second full season with the motor, so I do not know if or when the impeller was ever replaced. I have ordered a water pump rebuild kit.

The motor was used in Lake Eire until we brought it to the Chesapeake Bay in Sept of '08. I only found out about the flush attachment on the motor this week while search this forum for information. The Bay is a brackish mix, some saltwater, but enough I'm sure for some blockages to form.

Thanks for the help.

 

[rodbolt]

Re: 2000 Yamaha 15 HP Cooling issue

as far as the engine is concerned the chesapeake bay is salt water.
it may be that with the engine in the up position the water intakes are coming out of the water.
blow boat kickers are typically the most neglected motors on the planet.
wind is free and everything else outta be is the typical attitude .

 

[erniefish]

Re: 2000 Yamaha 15 HP Cooling issue

tell"in it like it is,rod bolt ,