Yamaha 90 water pump tube stopped up

[saboelte]

My 1999 Yamaha outboard 90 HP four stroke had the water pump impeller destroyed by something the other week. Ive replaced the impeller and the lower unit will pump water sitting on the bench, but I can't get the motor to pee. I'm thinking the the tube running up to the motor must be stopped up with pieces of impeller. Is there a way to remove lower unit and blow water or air back through there to try to clean it out.

Any help greatly appreciated.

[SeaDawg3]

how about disconnecting the hose at the pee stream and see if the hose and or pisser is clogged?

[saboelte]

I have. Even blown compressed air into the "pisser" tube and get no bubbles when when the motor is in the water. No doubt something is clogged. And it happened when the water pump impeller came apart.

[boscoe99]

Double check the model identity. Yamaha USA did not offer an F90 in 1999. The first F90 was offered here in the states as a 2003 model year motor.

Regardless, don't lose sight of the fact that water coming out of the tell tale is not water that flows through the block to keep it cool. Is the motor being cooled while running in the water even in the absence of water out of the tell tale?

Follow the hose from the tell tale inlet to the point that it attaches to the block. More than likely it is the exhaust cover on an F90. Remove the hose and back probe into the exhaust cover to see if any debris is in there. You might need to remove the exhaust cover to inspect further.

[saboelte]

Was thinking of wrong boat. It is a 2004 F90

Now I didn't know that the water out of the tell tale was not the water that cooled engine.

Went and played around with it, and took apart the water hose hookup on the motor that one would use to flush the motor. When motor is running, very hot water comes out of this.

Couldn't get anything out of tell tale even with probing it.

Would removing the thermostat give me an opportunity to blow out the tube coming from water pump?

[boscoe99]

Was thinking of wrong boat. It is a 2004 F90

Now I didn't know that the water out of the tell tale was not the water that cooled engine.

Went and played around with it, and took apart the water hose hookup on the motor that one would use to flush the motor. When motor is running, very hot water comes out of this.

Couldn't get anything out of tell tale even with probing it. So, you actually probed the block where the port is that connects to the rubber tube leading to the tell tale?

Would removing the thermostat give me an opportunity to blow out the tube coming from water pump? Nope.

Why do yo think the water pump tube is blocked? Is the motor over heating?

Have you visually looked up the water pump tube, to the extent that you can, and do you see debris lodged in it? If so, try and auger that debris back down and out.

One more time as many don't understand this - water coming out of the tell tale, or not coming out of the tell tale, has nothing whatsoever to do with cooling water flowing through the block. You can take a perfectly good motor, clamp off the tell tale outlet flow, and the motor will operate just fine. The tell tale is an indicator that the pump is working. Nothing coming out of the tell tale does not mean that the pump is not working however.

[saboelte]

Why do yo think the water pump tube is blocked? Is the motor over heating? Yes it is

Have you visually looked up the water pump tube, to the extent that you can, and do you see debris lodged in it? Yes and yesIf so, try and auger that debris back down and out.That I did and got several pieces of impeller out of it

One more time as many don't understand this - water coming out of the tell tale, or not coming out of the tell tale, has nothing whatsoever to do with cooling water flowing through the block. You can take a perfectly good motor, clamp off the tell tale outlet flow, and the motor will operate just fine. The tell tale is an indicator that the pump is working. Nothing coming out of the tell tale does not mean that the pump is not working however.

Still no tell tale water except at high RPM. Even then.....Overheat in about 5 minutes. Flushed with water for 30 minutes. Dug impeller pieces out of tube as best I could. I guess she is going to the shop to dig more impeller pieces out of the block???????