test prop

[Strahm]

Wanting to do some work on my 1973 mercury 850. Really need to be able to run it at home in a tank under load.
I have seen one video on youtube where the guy took an old prop and cut the fins shorter (left a taper to them).
Is this a feasible way of making a prop that won't splash water out of a tank, while still putting load on the engine?

If not where can I can a test prop for my engine?

 

[Texasmark]

Back in the '50's was in a Merc dealer and they used a round alum disc with louvers cut into it. It wasn't something you could easily make yourself. Only one I've seen and this was on 40 hp max engines. You obviously have to have a load on the engine and that obviously comes from pushing water around which means lots of turbulence. On an engine that large what I have seen more recently at another dealer was a square tank of about 4' wide x some depth x 6' long with a plate over all of it leaving just enough room to insert the engine. Water level was as low as could be and still cover the water pump. That worked good and apparently they were using the engines orig. prop as it really boiled the water but it stayed in the tank.

One thing that is easily forgotten. The cooling water from the engine is obviously returned to the tank. Keep tabs on the tank water temp.

Mark