Need help with MJ mod

[DriftRtist]

I have a maxi jet mod that has trouble going in the right direction. It will spin in the right direction for about 5 to 15 mins max. After that it starts to bounce around and then spins in the wrong direction. I tried to move the stopper bar as close as i can but that didn't do much. Does anyone know how to fix this?

[blakeoe]

save yourself the trouble and buy the new hydor. I have built tons of these mj mods. tryed all different builds and all combinations of tube and rods and still have not built one that works flawlessly. The last one i built works the best of all but every now and then it gets really noisy for a few days and if the power ever fails or i un plug it i have to hand start it. I wish i would have never spent the $$ or time on these things im buying 3 of the hydors.

[clevername]

<a href=showthread.php?s=&postid=9325559#post9325559 target=_blank>Originally posted</a> by DriftRtist
I have a maxi jet mod that has trouble going in the right direction. It will spin in the right direction for about 5 to 15 mins max. After that it starts to bounce around and then spins in the wrong direction. I tried to move the stopper bar as close as i can but that didn't do much. Does anyone know how to fix this?

Long story short, there are two problems which cause this. Your magnet is off center, or your prop is to big.

If you hear no clicking/rubing noises while its in the water try sanding down the prop.

For more info read the 200 post thread :)

[DriftRtist]

Well it turns out to be that the prop is too big. Funny thing is that I ran it without shaving the prop down for 5 months flawlessly. Then one day it does this. Damn, only thing is I sanded down too much and now I only have low flow....haha....oh well at least it works again.

[dhnguyen]

Well... First off this is a DIY project so if you're not really handy or the type who don't plan things out ahead before hacking away, the MJ mods may not be for you :)

The mod will only work as well as it was built IME.

[dhnguyen]

Oh yeah not all MJ pumps are made the same either. The back and forth jumping of the propeller is a clear indication that you are riding on the edge of what your pump is capable of turning. Usually shaving a little bit off the prop will fix that.

[sherm71tank]

dhnguyen knows what he is talking about. I have one of his MJ mods and it's totally silent and flows a wicked amount. I replaced a Seio 1500 with it and the flow really isn't comparable. I think the 2000 gph is conservative.