Mercury 40 hp 2cyl 2 stroke elpto 2002 OT548542

by Demo
(NC)

water comes from tell tale when cranking when engine starts water flow from valve stops and seems like exhaust comes from tell tale.Water pump has been changed all tube seals have been replaced. Thermostat and poppet functional . Compression is 90 plus on both cylinders have scoped cylinders to see if pistons and cylinder walls are damaged. None found! Has been starting very hard since problem started. Have tried it with muffs and in a water tank same problem when engine starts. Any Ideas? New base gaskets and exhaust bucket seals. Exhaust seems to be overpowering water pump. Could it possibly be a problem with the exhaust bucket being cracked and leaking into the cooling system. Have asked many sources of info on this motor and it has baffled them all! Motor has run like a champ in the past with no problems until this problems onset! Can you help? jodemit@carolina.rr.com