Maxijet mod chattering

[bc_slc]

Hello there. I recently purchased a maxijet mod from mjmods.com. i put it together this last weekend, put it in the tank the day before yesterday. It has some issues with chatter. About every 5 min or so, the propeller begins to chatter and tries to rotate in the opposite direction.

It is running on an MJ1200 that was previously running in the tank. I put it together using the "old" mod style as described on reefervideos.com with the small segment of airline tubing. I am using the steel rod which I have cut to the perfect length for my maxijet (took me two tries) and the prop assembly spins very freely on the steel rod. I also have the acrylic rod to prevent it from rotating the wrong way. The magnet/tubing/propeller unit is slightly shorter than it should be so it does have some play.

i am not sure why it is doing this. When I give some back pressure (putting hand over the exiting stream of water) it doesn't happen. This leads me to believe that the propeller may be creating a bit too much resistence for the maxijet, overwhelming the motor/magnet and causing it to try and rotate the opposite direction. i am not sure if i should (1) try and trim the prop, (2) try a newer maxijet motor, (3) extend out the tubing/propeller unit so that it has less play.

Before i go this far, any other advice on why this could be happening?

 

[dhnguyen]

this usually means that the propeller you useed is a bit too mcuh for the pump. Is it and older pump? Try trimming the propeller down a bit and it will resolve your issue. Easiest way to do that ius to dry run it without the shroud, using your hand to hold the shaft centered and run the prop blade against some sand paper.


D.

 

[bc_slc]

word up. The sandpaper was the perfect way to trim down the prop. Been running now for 3 hours and not a single chatter. Thx for the help man.

I ordered 2 more of these kits that just arrived today. Any opinion on the "new" vs "old" way of assembly. To review, "old" is with clear hard and soft airline tubing and the "new" way is with the black hard tubing that goes all the way through the magnet. Also, any preferences on carbon rod vs steel?

Mat

 

[dhnguyen]

Better to use the black airline that came with the original MJ pump. This is a much tougher airline and won't fail like the clear airline will in time.