Have Boat Questions? Ask a Boat Repair Expert.
Hello. My name is Tan.
It is possible. Have you tried to clear any debris that might be partially blocking the tell tale? Some times small debris get caught in the outlet. The thermostat should be serviced when the water pump is serviced along with the pressure relief valve.
Did you replace all worn parts in the pump or just the impeller?
Are you sure you got the water tube grommet # 60 in place? How did the end of the water tube look? Did you look for pin holes in the water tube?
Look at all the components in the diagram be sure they are all in the correct location. I would also pull t-stat cover and inspect for corrosion. The t-stat and pressure relief valve are in the top of the cylinder head. # 10 & 11.
When you have the pump inspect the water tube real close look for any kind of pin holes.
Post back with findings and questions.