Would someone be able to tell me how hot the crankcase gets on our Zens. Both stock and modified if that makes any difference.
Thanks for any assistance.

Regards
Tar

Because our purpose built engines are water cooled and unregulated too flow and temp of water flowing threw system it varies quite a bit. Now ideally the temp between stock or modified in a cooling system being regulated by end user is one in the same, water boils at 212* F at sea level.
Our engines RUN BEST with at minimum 170* and still run great mid 200's ! so long as carb mix is correct. You want a water cooled engine while operating WOT under load to stay 180/190*, do that your in the sweet spot.
I will note a lot of RC boaters never get engine hot enough and run a lot cooler than this. It can work fine doing so but at the expense of a bit of HP.

JMO,
Scott

Scott:
Thank you for the info. Now I guess I have to get a heat gun to know what temp I am at.
Thanks again.
Regards
Tar;)

I have found that if you run decent diameter hoses from the pickup you should not have any problems with overheating. Providing you do not have a clutch and idle the boat a lot, then you will require a water pump. All makers of clutches also make water pumps. Also just make sure there are no blockages in the pickup or waterlines. A regular check of the water oulet whilst the boat is running is also mandantory.
Hope this helps.

So running an engine too cool is robbing horsepower. Now I'm going to take some readings next time out at the pond. Just because you got me interested on this subject. LOL

Once you understand what the process of combustion is all about, that being creation of heat and the gas expansion that creates the push that moves the piston down from TDC.
What engineers refer to as BTU's ( British Thermal Units ) which in an engine that needs to keep its temperature within a range that engine will not seize or have heat related fatigue of parts, keeping and using the highest BTU's during combustion is helped if operating temp is elevated to the upper limit for type of engine it is. Liquid cooling is under the limit of boiling point of said liquid. Air cooled application can and do run much hotter but harder to mainain at a specific range as rpm and load is varied. Thus why liquid cooling is most desirable in engines.