Interesting Pee Problem

[pnoguy]

Hey fellers. I'm a FNG and this 1974 Merc 500 is my first outboard, and I'm learning quite a bit with it. Here is what I know regarding my tell tale:

1: Water pump has a brand new impeller and it works great. I also gather that there is no thermostat in this motor.

2: I know I'm pumping water and cooling the engine, because I pulled the brass plug and got a nice steady stream of warm water when running in the tank.

3: I'm getting significant amounts of warm water from the baffles by the anti cavitation plate, and also from the exhaust baffles below the bottom cowl.

4: The tell tale tube between the bottom of the power head and the pee hole is completely clear. I took it off and inspected.

5: I ran the engine in a tank with the tube removed, and got nothing from the outlet at the bottom of the power head. Not a drop.

6: I ran the boat on the lake for about 30 minutes or more, and the side of the engine never got what I would call hot to the touch.

7: Another good indication that I am pumping water is I have the classic old Merc seepage by a couple of my plugs.

8: When I pulled the lower unit the first time, it was full of sand and muck, and the impeller was completely shredded.

9: When I tried reverse flushing through the tell tale outlet on the bottom of the power head, water wouldn't go past it and it blew the hose off.

So, all that said, here are my questions:

1: Is the tell tale supposed to be putting out actual cooling water, or is it just a visual indicator that you are pumping water?

2: Since the thing seems to be cooling alright, am I safe to run it until I can pull the power head and really go through it?

 

[FLATHEAD MAC]

Re: Interesting Pee Problem

Im working on same motor, replaced water pump and had fery little flow at tell tale. You might have a blockage between the two, i took a piece of weed eater line and probed the tell tale, now getting mega flow

now if i can get the shifter and reverse lock cam to work properly

 

[Texasmark]

Re: Interesting Pee Problem

Since you know that you don't have a stat, you are probably plumbed off the exhaust manifold. As soon as you crank you should have a good strong stream which increases in strength with rpm. As Flathead did, you might check for obstructions in the pee line.

Temp obviously has to do with operating conditions and ambient temp. Warm to the touch after running in this kind of weather sounds reasonable. If you weren't cooling, you could sizzle spit on the block.

Mark

 

[444]

Re: Interesting Pee Problem

Sounds like you are cooling alright. Try blowing some compressed air through the outlet on the block. The air you shoot into the pee hole should exit through the exhaust, so if you put an ear up to the prop you should hear it.