Help please

"The other day my husband and

"The other day my husband and i took our boat out for a drive, immediatley we noticed the engine was overheating so we shut it off and loaded the boat up and took it home. We new immediatley that we should check the cooling system first, we replaced the water pump and checked the water pump impeller. This time we decided to use the water flush attachment rather then taking it to the river. When the attachment was hook the engine ran fine and was not overheating so we decided to take it to the river. Once again immediatley the engine started overheating. We brought it home checked the pump and thought maybe the pump was faulty so we replaced it again. However this time when we ran it out of water we submerged it into a bucket rather than the ear muffs. It sucked no water out of the bucket. I know obviously that the ear muffs worked because the pressure from the hose was circulating the water. What could be the causes for the water not sucking through the intake holes on the lower unit of the engine? We are at a loss we have checked the thermostat, water pump, impeller, im ready to give up and i dont want to.Please help"

"I'm assuming that this is

"I'm assuming that this is a Cobra drive?
Do you know for sure that the impeller is even turning, could have a broken shaft? Have hubby remove the pump housing and while your watching the impeller have him just quickly touch the key to see if it moves, you don't want to start the engine so a jumper wire from a good ground on the engine block to the neg side of the coil will prevent this.
If that's ok then make sure the stainless liner is positioned correctly inside the housing and the big rubber o-ring or gasket on the housing itself is ok, and check the small hose that attaches to the housing for blockage (can you blow through it)."