all right, so I pulled the exhaust bypass cover off along with the inner baffle, and didn’t really find anything that lead me to believe there was water getting in through the exhuast holes in the cylinders. There was some pitting on that inner baffle, but the gaskets didn’t show anything that indicated water getting into that exhaust compartment.

I pulled the lower crank seal, which is now called the crankcase head assembly, and found the seal on the inside of this seems to have failed. So I’m guessing this is where the water was coming in through, or perhaps somehow pressure was stopping water from the pump as per what everyone was talking about. Am I correct in this conclusion?

The water I found in the cylinders was probably from when I ran the motor in the test tank last friday, and what was left over in the crankcase/cylinders. Whatever water I used to pump through the motor today via garden hose probably just went as it should through the cooling system and passed through. I haven’t found any blockages in the water system; the thermostat was pretty well clogged up with debris and the overboard "L" was plugged nearly solid with some small pebbles. This is probably why I could barely get water through the cooling system with the garden hose today.

It’s probably a good thing this motor presented issues. I happened to be looking at the intake manifold with the carb off, and noticed the center screw on the manifold was missing. Then I realized that somebody installed a 20hp manifold on this 35 hp motor…the intake orifice is clearly the wrong one…so looks like I’ll be replacing that with the correct manifold!

They probably left that screw out of there to allow a little more air/fuel mixture in, but where that logic came from makes no sense to me, as that restricted manifold looks like its only about 60% of the size of the normal 35hp manifold.

So this motor actually had 4 things wrong with it…95% blockage of the telltale orifice, 95% blockage of the thermostat, failed lower crank seal, and totally wrong intake manifold (complimented with missing screw).

What’s impressive is the motor started up on the first 2 seconds of the key-on position after I tested for exceptional compression, pressure test-OK on the gearcase with lube change, and refurbished the ignition system.

As the old rules state…spark, fuel, air = RUNNING. Not necessarily right, but it ran immediately….

The motor I started this thread with was transplanted to another pan/leg, so I’ll get to it in a couple of months. I am pretty sure that the near complete clogs in the telltale and thermostat were the culprits. Finding the faulty lower seal with water in the cylinder(s) and the incorrect manifold just happen to be bonus items I stumbled onto with this one.

The other thread I started was utilizing the original leg, gearcase/pan of this motor, and is a different powerhead.

I tore the exhaust cover off and didn’t really see anything that indicated exhaust making it into the water inlet to stop water flow with this 2nd 35hp motor (which coincidentally is an ’81). The stainless steel baffle appears OK. I am going to button up the motor tonight, run it in the test tank, and if it overheats/stops water flow again, mount it on my boat tomorrow and try it on the river. If it overheats again, well then we know its a faulty seal in the impeller housing or something related to that.

This one is starting to get frustrating because I have put a solid 20 hours of labor into it, but this i the best way to learn I suppose!