Arturo, two years ago I was in your position exactly and this website has been very helpful (especially Alan Gomes for us E26 owners. He knows everything about them and is a good teacher). The boat is more fun than I expected and easy to singlehand. It's also a great boat to learn about boat ownership on, because everything is smaller and cheaper. Congratulations!
At first I was very worried about the lack of an electric bilge pump in my boat. Now I still have no electric bilge pump and it has become a very low priority for me. Brooklyn has a lot more rain than Los Angeles, however, so if your boat takes in much water in the rain then you're facing something different. My boat is nearly watertight in a hard rain. (The deck-stepped mast helps.)
The prior owner of my boat had tried to install an electric bilge pump in the forward compartment but it won't fit next to the foot of the manual bilge pump intake that Ericson shipped the boat with. (I suspect he put it there when his sales broker told him that his boat needed an electric bilge pump, because there's no sign it was ever used.)
Note that Ericson manufactured this boat with only the manual bilge pump. They knew something about their boat.
The pandemic forced me to leave my boat in the water untouched for five months last year, and because the stuffing box didn't leak, there was no problem.
I recommend getting familiar with your stuffing box before worrying about an electric bilge pump. If it leaks more than a couple of drops per minute at rest, and you can't tighten the nut to stop the leak, then you need to replace the packing material. But even if it drips a bit, you can measure the amount of water that comes in by sucking it out of the bilge and doing some math. At one point I was taking in 1 liter per week, so if you know that, you just have to keep on top of it. The bilges will hold at least 4 gallons (15 liters) before there's enough water for the manual bilge pump to reach it. Get used to how much water comes in and how regularly you can check on your boat.
You will want to learn how to get water out of the three separate bilges through those tiny holes. Plastic pumps used to suction oil are cheap and available at Home Depot, and will last a while, but they eventually corrode. I find a plastic medical syringe the easiest. See below. This would be crazy on a large boat, but with the E26, you usually only need to suck out a couple of liters.
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In general, I recommend heeding the advice that you will see all over this website:
Just start sailing your boat, and figure out what you want to change as you grow familiar with her. Plenty of things that I thought needed to be tackled when I bought the boat I have simply forgotten about. There are so many different systems to learn (e.g., the head, the engine, the stuffing box, the boom-internal lines), that it can seem overwhelming at first. Just learn each one as you go along, bit by bit, and keep sailing. (But I just realized this advice is harder to follow in Brooklyn during the winter!)
P.S. Your Yanmar might not present this problem, but stuffing box access isn't easy. I do it over my engine, facing aft, after removing the coolant overflow container which is in the way. The problem with this is that the engine can't be hot when you adjust the nuts.