1969 55hp outboard. The impeller looks good but there is no water exiting the lower unit while running. The "hot" light came on and I immediately shut it off. I pulled the thermostat after it had cooled and started it up again. No water was present in the thermostat area. Any ideas what this means? It all started after running through a few sand bars. Is it possible there is a clog somewhere? If it is how do I remedy it. I can't find anyone in my area who will work on an older motor. Thanks.