Fischer Panda Generator stops after about 1 hour

[Golden-Spirit]

Fischer Panda Marine Generator
Model PMS 4500 FCB
Serial number: BO1 034 041
Fitted by Fischer Panda on 14/03/2007
Run 2100 Hours

I have a technical problem with my Fischer Panda Generator.
It starts but cuts out after about 1 hour. The time it runs varies between 50 minutes to 1 hours 10 minutes. After some hours or overnight the generator will start again and run for approximately another hour. During the time the generator is running the AC output voltage is normal.

The obvious thought is overheating, however during the period the generator engine is stopping there are no indications on the remote control panel as to the reason; exhaust temperature, cylinder head temperature and oil pressure lights are all green.

I have replaced:
a.) The fuel solenoid assembly
b.) The external HARDI fuel pump, including hoses and upgraded the wiring
c.) Fuel filter
d.) Impeller
e.) Impeller drive belt
f.) Air filter

I have checked all wiring and under close supervision carried out the following tests, all of which have proved non-conclusive
1. Removal of exhaust temperature sensor lead as it is normally open
2. Removal of cylinder head sensor lead as it is normally open
3. Bypassed the thermo-switch in the winding as a fault here does not show on the control panel. As this thermo switch is normally closed linking the fuel solenoid relay to ground I connected the –Ve side of the relay permanently to ground for the duration of this test. No difference, thus assume I can eliminate the thermo-switch.

Does anybody have a suggestion as to what might be wrong and what else I could try?

Any help much appreciated.

Thanks.

Michael
s/y Golden Spirit of Islay, currently in New Zealand