1966 40 hp RKL cooling questioin

[pz5r9n]

Our 1966 40hp electramatic is overheating within 5 mins of being in the water, thermostat appears to be working, any tests we can perform to determine if the impeller is working properly? and does anyone know the OEM part number for a new impeller if that is required?

 

[F_R]

Water pump should always be the first thing to inspect if it is overheating. Original OEM number was 377230, now changed to 0777213. Or, Sierra Marine aftermarket part number 18-3083

 

[oldboat1]

^^^always first on the list. How did you determine the t.stat was working?

 

[pz5r9n]

tstat was open when engine was hot, closed when it cooled off. ​thanks for all the help

 

[oldboat1]

You need to see water sprayed out of the opening on the back of the leg after only a couple of seconds after starting -- t.stat has a bypass for warming up. If no water, assume the pump isn't working. After the t.stat opens, the flow usually increases (the way you often tell the t.stat is opening, although doesn't tell you the temp at opening -- determine temp of opening/closing by pulling out the thermostat and testing it.)

 

[HighTrim]

The super quiet legs, don't discharge very much water, especially when the stat is closed. Just a misting. IF the condition of impeller is unknown, or the age of it, always change it. Inspect grommets, housing, wear plate, etc... while you have it apart.

 

[oldboat1]

Hope you post findings....

 

[pz5r9n]

new impeller and tstat seems to have solved the overheating issues. now if we could just get it to shift