Testing motor in a tank

[buldogbil]

Is there a rule of thumb for testing a motor in the tank ? How long is it safe to run ? How long does the motor take to warm up to see if it is over heating ? Is it ok to use a lazor thermometer to check the temperature ? Where do I take the temperature and what should it be ? All my motors are mostly under 10 hp.

 

[piperjak]

You can run them as long as it takes to satisfy the operator. Best to run in neutral and not overrev. If it is not pumping water - 1 minute will get it hot. Check the temp at the cylinder casting area and you will be looking at about 100-140 degrees. It is hard to get the temp very high with a good water pump and the motor not producing thrust or in gear doing work.