Did Marina Rip Us OFF?

by zena
(delaware)

We have a 2002 mercury 60hp outboard engine on a 20 ft pontoon boat.We had it in the shop

for a high pitched warning buzzer indicating overheating. After 1000.00 in repairs including impeller repair kit, sender- temp part , numerous gaskets and a new theromostat it still had the high pitched buzzer going off. They "fixed" it again by taking out the new thermostat saying this particular engine can be run without a thermostat. The high pitched buzzer still goes off occasionally. Boat does not need oil as we check for that constantly. Does this repair job sound right?