The impeller and housing look good.
I greased the impeller like they did in the video and put it back in - I did get water flowing out the exhaust. It was very little water at low RPM (800) and good flow at 1400 RPM. But, it seemed like the thermostat did not open - the temp went to maybe 170 and I shut it off. I removed the impeller and the grease had clogged the little water drain port in the cover - so I wiped off all the grease, and unplugged the cover drain, and put it back on. Then I pulled the hoses from the thermostat cover - no nasty stuff going on around the hose ports. Reconnected hoses and restarted motor and got water right away - I did throttle it up to 1200 RPM for a moment after starting it. The temp hit 160 *F and stayed there for 7 minutes then I shut it off. I'm ordering 2 new impeller kits and 2 thermostats and gaskets, and will get some new hoses as they have been on the boat for several years. They don't look real bad but there are a couple iffy areas on a couple hoses.
(From Lou's post) If water wasn't getting to it from the water intakes in the lower unit it would show some signs of burning most likely. Did the engine that this came off of have any earlier history of overheating? No
What I would do is this:Lou, This info below is what I was looking for - as I was wondering - how to check for blockages. I will go through these steps when I get the impellers and the thermostats (in a few days) and just get to know the boat better. THANK YOU!  .
1. Remove the thermostat housing on that engine, check all the passages for blockage/old impeller parts or rust clogging. Clean out any clogging you find, re-assemble with a new thermostat, gasket and use OMC gasket sealer on the bolts. That will save you from breaking a bolt the next time LOL.
2. Next, with the impeller housing still off:
Hook up the water muff to your hose...slide them on the drive and hold them tight to the lower unit. Have some one turn on the water will you look for water spurting out the right side opening in the impeller mounting surface. If water spurts out, this verifies that the water intakes are not clogged and the water tube gaskets in side the drive are OK.
3. Now go up to the engine, disconnect the hose from the transom mount to the thermo housing on that engine. Stick a garden hose in the end of it firmly so it won't fly out when you turn on the water. Go to the back of the boat and look at the left side opening on the impeller mounting surface. Have some one turn on the water. Water should spurt out verifying that the hose from the transom mount to the PS cooler and from the cooler to the thermo housing is not blocked. Sometimes if an impeller fails, pieces can get lodged anywhere from the impeller to the thermostat housing.
If that's all good, reconnect that hose.
4. Now disconnect one of the feed hoses for the exhaust manifolds at the thermo housing. Hook up your garden hose to this hose and have someone turn on the water. Water should fill the manifold, and come out the exhaust housing in the transom mount, you should hear it spill out on the driveway. Do the same with the other side. If either side fails you have a clog somewhere, it could be rusted riser/manifold passages or even a stuck exhaust flapper in the Y pipe.
These are low pressure high volume systems, they depend on a high volume of water to carry away the heat of both the engine and exhaust manifolds. Anything that causes a restriction in flow will cause over-heating of the engine, exhaust or both. You need to check through the whole system and eliminate possible causes.
Keep in mind that when the engine is cold and the thermostat is closed, the water coming in bypasses the engine completely and should be going right out the exhaust. This is why you should see water coming out the exhaust right away. When the thermostat opens, it allows hot water to leave the engine and go out the exhaust manifolds. At that point (about 15 min of running time on the hose) you will feel the exhausted water get warmer and you can tell by taking readings on the intake manifold with an IR temp gun that the 'stat is opening (the area right under the thermo housing will read about 155-150 and the big hose to the front circulating pump will get hot).
Good luck with it.....
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