Water pumps for a 1973 65hp Johnson out board

[Trains1938]

Hi, I have a 1973 Johnson 65 hp out board motor and I was running it with a set of ear muffs. I did not see any water coming out of the motor where I thought it should if the waster pump was working. How can I tell for sure that the water pump is working? Can't find anything on the net that shows this issues.

 

[F_R]

As I have said many times here, you cannot test a water pump by running on muffs. Ideally, the motor should be on a boat, on the lake. If you have a large enough tank to submerge the lower unit up to the stern brackets, that is better than nothing.

Do you know the history on your motor? When was the pump last changed? Don't wait for it to fail before renewing it. Finally, if it still has the old aluminum pump housing, toss it and put in a complete new pump with a plastic housing with stainless steel liner.

 

[Trains1938]

Hi F_R, Thanks for the come back. I talked to my local Johnson repair shop and they told me that if the exhaust plate (that is on the left side of the motor) stays cool to the touch, the water pump is working. So I ran it for about 10 min and the plate stated cool. However, your point is well taken. I do not know the history of this motor. So I do not know when the water pump was change or even if it has ever been changed. Your comments about the stain steel is well taken. I think I will check it out. If it is the old type I will change it. Thanks for the advice.

 

[racerone]

Most folks change the impeller after their wallet has been damaged by one that failed.

 

[emdsapmgr]

The overboard indicator (telltale) did not come out until 1978, so your engine was not designed with one from the factory. On these older units, there is a way to determine if the cooling system is working. Connect the engine up to some muffs and start the engine. Hold the palm of your hand back by the two exhaust relief holes at the top/back of the midsection. Initially, you will just get a little puffing from the holes. After a minute, the stat will open. When the stat finally opens, you will start to see water droplets form on the palm of your hand. This indicates that the pump is working and that the stat has opened. Normal situation.