My motor is not pumping water. I had it running fine last year and wanted to take it out for the first time this week. Put it in a barrel and started right up but no water coming out. I took the lower unit off thinking the impeller might have been bad but it looks fine. ( I replaced it last year). Put it back together making sure the water tube is going in correctly into the impeller housing. Still no water! What am I missing? Please help.