1992 Yamaha 40 MSHQ/ what have I messed up

Hello everyone, The other day I was wiping down the engine and I removed the tell tale hose to get it out of the way. I blew through the hose and debris came out so I looked at the fitting it came off of on the block and it looked pretty scaly. I took a small brush from a carburetor cleaning kit and went to work. It cleaned the opening well. Then I decided I would grab the air hose and blow into it. The tip fit right so I gave it a good blast. I heard air flow down in the lower unit. A minute later I noticed what looked like green lower unit oil and water. But it didn’t smell like gear oil and not much came out. The next day I removed the top plug to check the gear oil. It released a little pressure and a little oil came out. I figure since it had some pressure in it I shouldn’t have any leaks. I know I blew air directly into the impeller housing and there’s a seal under it. I’m still concerned that I may have did some kind of damage. With all that being said I’ve been working on this boat for a while (project boat ) and it’s had a lot of time put on it in the driveway mostly idle. A few revs while in a tank. So I know it needs some wot to blow out the exhaust and I’m supposed to finally take it this Saturday. I’d sure appreciate another opinion so I will stop worrying. I’ve put a lot of time in this engine and everything is set right for running unless I need to adjust the carburetors while on the lake. Thanks for taking the time to read my story and I’m grateful for any opinion. If I did screw up I don’t want to take it out until it’s fixed.

Could be it had pressure in there from the hot sun, I have noticed that if it's overfilled, that can happen. Was the sun out that day? Realistically, there is no way that the air shouldn't safely escape from your blowing into the cooling system. When you take it out, just make sure tell tale is squirting water....then keep an eye on it as you may have knocked loose some scale.

Thank you for the response. It’s greatly appreciated. I don’t seem to have any leaking seals. When I get a used engine I change the gear oil . Run it a few hours and change it again to make sure there’s no problems. So I drained it after another run and no water. Oil looked like it did the day I put it in. Still can’t figure out what it was that I blew out of the water pickups. It looked green blue like the gear oil. You may be right about a little over full. When I removed the top plug it had a little pressure against it and some oil ran out. Thanks again.
Keep a tight line!

You too. Waiting for smelting season on L. Superior in the next 2 weeks. The silver little delicacies are "on the menu".