1957 Johnson 7.5 hp water pump issue

[sixstringnut]

Hi all I am a newbie so please bear with me!
i have a 57-7.5 Johnson that is giving me fits with the water pump!
upon starting the pump pumps water for about a minute and just stops!
I have flushed the power head looking for blockage, new impeller and I still cannot get it to pump Continuously!
Any and all help appreciated
Thanks sixstringnut

 

[racerone]

In your test bucket the water must be 6 to 8" above the impeller.---Yes 6 to 8".----The pump is not self priming and it does not pump exhaust bubbles very well !!