Well today I got out the barrel and ran the engine in it as Crosbyman suggested. I got water spitting out the top discharge as you can see in the pic. The barrel level was about at pump level but not quite as high as it would be with boat launched. Nor there is any evidence of scorched paint nor any smells on engine anywhere. In fact after running for 25 minutes at between 400 and 1400 RPM nothing anywhere on the engine got too hot to grab or put fingers on. My little Klein IR gun never found a surface over 107 Deg F except a couple of spots on the port side bypass covers(?) that has the fuel pump vac hose fitting on the lower and the cut out switch on the upper. They were highest at 128 Deg F. Now to see if I can get the pic file size below 2megs! Well I don’t know where the pics went!?! I expected this to be a continuation of the post thread.  More art than science, and I’m not an artist!!!

I think it is good news. I am modifying the hose adaptor that screws on the side so mose water goes up into the pump instead of gushing out the intake screen on the skeg. Should be simple. But I always say that just before it turns into a three day job.

Definitely gets your hand wet if you put it in the output stream of that upper discharge port, but at idle the temperature is not at all uncomfortable, just warm. I should have put a container in the stream to try to quantify the volume of water! But at about 14-1500 rpm it’s too hot to hold your hand there for any time at all. I don’t think the heat is in the water but actually in the combusted gases coming out there. I wonder why none of the engine pieces are showing this same increase in temp. I guess that water is REALLY doing its job!? OH, I forgot to mention that I have a copy of the Red Book. Down loaded it at the suggestion of one of you great guys a couple of years ago while I was rebuilding the lower end. Lost of info there! Thanks for the cooling flow diagram. I think the RDX-20 and 21 must be same enough to not matter. Well I will try to get this one out on the water, run it up and see what the temperatures look like at various points after a hard run.  Thanks all!  Tom Alex