TOPIC: 1965 Merc 39 Questions

I picked up a little 1865 Merc 39 3.9 hp for cheap. The previous owner had broken the float bowl cover / filter base. The shifter spline was not engaged to the lower unit, and the handle broken off. I fixed up all the quirks and got it running today. One issue I had right away, was my normal Mercury fuel line fittings are too big around to fit. I haven't seen a smaller size? I managed to rig a hose and clamp to it for testing.
The previous owner says that he replaced the water pump impeller.
At first start there was not a lot of water coming from the exhaust port under the powerhead. At starting RPM, eventually a good amount of water would spray out, but would stop completely at higher RPM. Some adjusting of RPM would bring back the water spray. I'm not used to having an engine with out a tell tail spray hole. Is this normal? It sure is hard to check power head temps when you need the cover on to start it.

there is a 1/8 in tell tale on the motor may be blocked. you can add your own. look on top of the block right rear as you look down for a 1/8 pipe plug. use that hole to add a hose for your new tell tale.

I've looked all over for a tell tail hole, it isn't in any areas that I've seen on motors running on YouTube. Looks like in 1968, the tell tail is on the starboard side about where the fresh water flush plug is on mine. A video claiming to be a 1965 has it on the port side just under the cover handle.
1965 Merc 39 video
Mine is black, silver and gold, but no red stripes like the one in the video.

I did try pulling the flush plug at one point, and no water came out. In theory I could drill an 1/8" hole in the flush plug too?

I found a different video with a motor that looks like mine. No sight of a tell tail that I could see.

1965 Merc 39 video 2

So I decided to pull the powerhead to check out why my flush port was plugged. It turns out the last time the gasket was replaced, it didn't have a hole to allow water to flow! Now that I see where the flush port is in relation to water jacket flow it wouldn't be the best place to add a tell tail to make sure the entire engine is getting water.
I also could see where the tell tail is supposed to be. Thank you Dave for the advise. I just could not see that tiny hole packed with black carbon next to the Phantom black paint! One more reason I like the Cloud White Mercurys more. Lol
Now I need to order up some water jacket and carb gaskets. Also broke all but one screw in the exhaust water jacket. I still need to drill one more out.