pumping water probs

[dellboy]

Hi, I’m having trouble with my Tohatsu 4hp 4stroke. It has stopped pumping water through. The impela was new back in the summer and I’ve had it all to bits and checked the water pipe is clear. I greased it all up before re-assembly. It pumps water through perfectly for about 20 secs and then slowly dies to a slow steady drip
Any advice would be greatly received.
Thanks Nick

 

[VicS]

Checked that the telltale itself is not obstructed by a bit of debris ?