Johnson 75 water pmp

[ericulvila]

Installed new pump with complete kit. Water pumped good fro three times out. Started to get weak and then completely quit when I put the muffs on. What should I look for. Maybe the key was wrong. I used the white one that came in the kit. Which way should it go on the shaft?

 

[joereeves]

Installed new pump with complete kit. Water pumped good for three times out. Started to get weak and then completely quit when I put the muffs on. What should I look for. Maybe the key was wrong. I used the white one that came in the kit. Which way should it go on the shaft?

It would help if you included the model number of that engine so that we know exactly what engine you're speaking of.

If the driveshaft has a flat area that the impeller key goes in... having the flat area facing you, the tapered portion of the plastic/nylon key faces left. It would only slide into the impeller one way anyhow.

When running on a flushette... have the water turned on full force. Make sure that the flushette doesn't vibrate off of the water intake area.

Don't assume anything..... drop the lower unit to double check your work.

 

[ericulvila]

Installed new pump with complete kit. Water pumped good fro three times out. Started to get weak and then completely quit when I put the muffs on. What should I look for. Maybe the key was wrong. I used the white one that came in the kit. Which way should it go on the shaft?

Thank for the reply - I will pull it check. its J75TRLCIM. On you tube there are videos showing an o ring that is installed under the impeller, also the parts diagram does not show one. Does this model use an oring between the impeller and wear plate?

 

[joereeves]

Thank for the reply - I will pull it check. its J75TRLCIM. On you tube there are videos showing an o ring that is installed under the impeller, also the parts diagram does not show one. Does this model use an O Ring between the impeller and wear plate?

Originally No.... However, if one purchased a new complete water pump kit, that might be possible but if so, the O Ring would be included with the kit and the impeller would have a groove manufactured into one side of it that would accept the O Ring. The O Ring does not simply sit under the impeller.

 

[fdrgator]

So you are testing with muffs on? Water pumps do not "pump" when running on muffs. They only allow water to pass through. In other words, you cannot test a water pump on muffs. But you certainly can fool yourself

 

[joereeves]

So you are testing with muffs on? Water pumps do not "pump" when running on muffs. They only allow water to pass through. In other words, you cannot test a water pump on muffs. But you certainly can fool yourself

In agreement with FDGator, but I would add:

True to a degree, hence the reason for the necessity of having that old garden hose turned on full blast on high horsepower engines when using a flushette. Water must be forced to the pump as it is not a self priming type pump and must be kept full of water via another means (hose pressure). However, a good normal functioning water pump will greatly increase the velocity of the water (visually noticed) as compared to a damaged water pump.

The above being my reasoning for visually inspecting (dismantling) the water pump assembly when encountering a overheating engine to be the number one step in troubleshooting.