Sorry I haven't been responding to this thread lately. I have really been feeling under the weather.
Anyway, I have done some more testing and experimenting, and these are my observations, FWIW:
The placement of the intake is vital to the flow of the pump. Look at the final post by thunt (the guy who started this thread
) and see what problem he had:
thunt said:
I seem to have come to a halt on this project. I used large dia tube to go around the propellor as a guard. When this is in place, the propellor will not spin. I can only think the tube impedes the water flow and stops the prop from spinning. As soon as I take the guard off, it spins again.
This exact same thing happened to me with my existing unit. Tim, if you are still following this thread, I think that using the original shaft of the Maxi-Jet is too short, and it can't pull in enough water from under the propeller.
When this happened to me, I could not for the life of me figure out what was wrong. Turns out that I shortened the shaft only about 1/8" to 1/4" (if I remember correctly) and this brought the propeller down closer to the body of the MJ1200. This tiny difference amounted in going from having the unit work perfectly, to shaking and sputtering and being non-functional. Note that this is even with the huge slits that I cut in the side. Its not only the size of the slits, but also the location that is important - you need enough room under the propeller so that it can pull the water in.
One other point of interest is that I think that it is still possible to do this mod with only one supported side of the titanium shaft (the stock shaft that comes with the MJ). It all has to do with stability. If you glue your airline shaft onto the magnet very straight, and if you attach the propeller on straight, you shouldn't get hardly any vibration at all. But if you trim your propeller, you ruin almost any chance of ever getting the whole thing stable. Again, the magnet is still spinning independently of the inner fixed shaft, but it is only supported on one side. Just a thought on another possible way of doing things.
I tried this for about a day and it was working fine, but I eventually took it out because it was making too much noise. (I thought it was due to the shaft vibrating, but I couldn't see it wobbling at all.) I then replaced it with my double-end support version, and even though the shaft is completely rock-solid, it is making even more noise than before!
I can't figure out where the noise is coming from, I have to go shut the pump off now, it is giving me a headache....
