Westerbeke BTD 8kw Diesel Generator - voltage problem

I have the above generator in my trawler. After starting it and letting it run for a few minutes, I put a load on it (usually my Xantrax charger and / or the hot water heater. Sometimes, after a short run period, the voltage spikes up from 120 V to around 160 V. The charger kicks out and the hot water heater too. If I shut down the generator and re-start it, the voltage resets to 120. Alternatively, if I let it run for five minutes or so, it will re-set on its own.

Any ideas on how to deal with this problem?

Thanks

Stephen

Stephen, welcome to the forum. To me it sounds like a thermostat problem.

Thanks for the reply. But I'm not quite sure what you mean by a thermostat problem. The spike in voltage can occur within five minutes or so from starting up the diesel generator. So, the engine is still getting up to temperature.

Please explain your input in a little more detail
Thanks
Stephen