8 hp not pumping water

[aux1205]

8hp yamaha, model 8SG, new water pump kit installed, no blockage, water tube, pee hole and head clean, air flows thru, but it still wont pump water out of pee hole. Water will flow thru when hooked up to flushing dog ears???????<br />I did notice when I block the end of copper water tube out of pump going to head and pump air into pee hole I hear the air escaping some where by the top of tube. Think a porous tube could be cause?

 

[Grant S]

Re: 8 hp not pumping water

I had a similar problem on my 2stroke 8hp, it turned out to be the gasket under the powerhead.<br /><br />If you place the motor in a drum of water with the level above the pump in the leg, does it pump?

 

[aux1205]

Re: 8 hp not pumping water

Last season when the pump was rebuilt it was pumping in a barrel.

 

[aux1205]

Re: 8 hp not pumping water

How hard and how much of a job is it to change the gasket under the powerhead?

 

[aux1205]

Re: 8 hp not pumping water

Also, I forgot to mention that I could feel air coming out of pee hole.<br />At first I thought impeller blades were bent wrong but I found on this forum that to install turn shaft clockwise while installing cover. This would cause the blades to bend back facing counterclockwise, which the blades were. Is this process correct? I have found nothing in my Yamaha repair manual stating which way the impeller blades should face.

 

[Al Kungel]

Re: 8 hp not pumping water

aux1205,<br />I have a 8hp High Thrust and had a similar experience this summer. This is a brand new motor and it is suggested that the motor be flushed every time after it is used in salt water. One morning I started the motor and I noticed that no water was coming out of the pee hole and I thought what gives. Anyway my son noticed that I had not hooked up the flushing device to the cap that is on the side of the motor. That is all that it took - hooked it up and all was well. Love this motor.

 

[bigbrownbuku]

Re: 8 hp not pumping water

pickup a genuine yamaha service manual first.<br /><br />powerhead removal on that engine is as simple as it gets. disconnect a few wires(stop switch). remove the bracket holding the throttle cables (pop the links off), undo the ingear no start cable at the pull start bracket. disconnect the fuel line at the carb/fuel pump, disconnect the choke link. underneath you will find 6 bolts holding the phead on. 2 are hidden somewhat between the engine mounts and the trunk.

 

[aux1205]

Re: 8 hp not pumping water

Thanks for all the information. I know what I will be doing this weekend.

 

[Lasse Lehtonen]

Re: 8 hp not pumping water

The air coming out of the pee hole may be exhaust fumes... If the cylinder/exhaust is leaking pressure in the cooling system those gasses in the cooling system will fill the upper parts of the cooling block and water level is below the hole where the water gets to the pee hole. If this is happening the water is flowing thru your engine, but you just dont see it. This is also causing the motor to owerheat, the whole cooling block needs to be filled with water.

 

[Real Ale]

Re: 8 hp not pumping water

Originally posted by ^Eki_Virtanen^:<br /> The air coming out of the pee hole may be exhaust fumes... If the cylinder/exhaust is leaking pressure in the cooling system those gasses in the cooling system will fill the upper parts of the cooling block and water level is below the hole where the water gets to the pee hole. If this is happening the water is flowing thru your engine, but you just dont see it. This is also causing the motor to owerheat, the whole cooling block needs to be filled with water.

Sounds like what is happening on my motor. What's the likely cause of "the cylinder/exhaust is leaking pressure in the cooling system"?

 

[rodbolt]

Re: 8 hp not pumping water

DO NOT run that motor with the hose connector on the side of the engine. its not designed to supply adequate water to the pump when running. its strictly for non running flushing. can destroy water pumps in a very short time.<br /> could be a powerhead gasket failure or a pump failure or a head gasket failure. now ya just gotta go find it. I dont think the G model has the flush port.<br /> if the motor was ever started with the pump not submerged or no muffs there is a good possibility that the pump failed. <br /> I just redid one last week after a large argument. I did a pump job and cooling system tune up on a volvo SX 5.7. man brought it back a the next day with a totaly melted pump hollering and whineing. I finnaly got the story from his wife. seems he had left some stuff on while prepping the boat the day before. he launched and the battery was dead, he pulled it back and used his truck to jump start it on the trailer and let it run"just a few minutes" to charge the battery. then launched and proceeded to fry the motor. burned all the exhaust hoses and melted some wiring. now he is hollering lawsuits and such. I just gave him my attorneys number. I aint paying squats .<br /> the same will happen with most outboard pumps. run it dry 30 seconds and a brand new pump is a junker.