07-21-2007, 03:20 PM #1
How freely should the impeller spin?
I've got a project ski going on, and I'm now installing my rebuilt jetpump. I've run into something that I'm not so sure about though. After tightening the impeller to the specified torque, how freely should this thing spin? I've got all new bearings, seals, o-rings, etc. This is between stator, stub, and impeller, unit is not connected to wear ring.
Mine spins alright, however it's nothing that would spin on it's own. For example, once you stop pushing it the impeller stops immediately. It pushes with finger pressure, just not as easily as I would have expected. I have nothing for comparison as this jetpump was toast when I got it.
07-21-2007, 03:29 PM #2
With new bearings and seals it should spin smooth. The bearings are sealed and filled with grease. There will be some drag.. If it spins by hand and feels smooth you are good to go.
07-21-2007, 03:36 PM #3
10-4, thanks beerdart. Impeller doesn't make contact with stator, however it's very close. It spins smooth, just requires more force than I would have expected as there's a decent amount of drag. I suppose the drag comes from the contact between the spacer and grease seals, even though it's all greased up.
07-21-2007, 03:51 PM #4
Quick update: Ok problem solved, and it was operator error.
The rear bearing wasn't completely seated by about 1mm. Instead of the spacer supporting the force, it seems to have put a side load on the inner races between the bearings. Fully seated the rear bearing, spacer sits snugly between the two, and the force trying to squeeze the bearings together is now properly supported by the spacer. Rookie move.
07-21-2007, 04:10 PM #5
07-23-2007, 07:32 AM #6
- Join Date
- Jun 2007
i have a 96 slt780 bored 2 mm over scoop grate hot seat muffler water box and vortex breathers, just ordered high performance ride plate.what would be the best impeller to run.ps right now i can almost run with frinends 1100 yamaha. thanks wayne
07-24-2007, 02:16 AM #7
- Join Date
- Oct 2006
- Cleveland OH
What are you looking for, top speed or acceleration. I'm assuming top speed if you want to hang with the big boys, but you may lose some abilty to pull 3 people or a tube. If speed is what you want, send Jetskimn a PM. He does alot with Nu Jet impellers from what I hear.
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