Hobby King Jet Pump
I recently purchased a Hobby King jet unit and was very disappointed at the quality.
For a start the ball bearing bore was .015" (.38 mm) out of round. As a result the inlet halves wouldn't clamp together.
The screw on one side of the bore was stripped. After helicoiling the two screw holes on either side of the ball bearing housing ,
to #4-40, I very carefully rebored the bearing bores to .001" (.03 mm) undersize on the bearings.
This also aligned the bearing bore with the nozzle mating surface. However, this lead to binding on the impeller shaft.
A check showed that the shaft had .005" (13 mm) or more runout depending on how it was held.
I held it on its center and the stator bearing surface which gives the least runout.
The shaft was also undersize, so a new shaft was made. The impeller has almost .040" (1 mm) clearance.
Since 10", full size impellers often run less than .010" (.25 mm) clearance, I would expect this to seriously effect performance.
I trued the impeller and the stator (They were a few thousandths out of round with their bores.),
drilled and tapped the stator for a grease fitting, and bored the nozzle out a little for a wear ring.
It is .080" (2 mm) thick UHMW held in with a press fit and CA.
There were other issues with play in the steering and trim nozzle as well.
See the discussion on the [link=http://modeljetboat.com/forum/index.php?topic=652.0]Model Jet Boat forum[/link] for others' solutions that I also used.

ORIGINAL: phillio35

hi mate ive just ordered a hobbyking jetdrive any views on them