Berkeley Jet Got Knock!

[stevecat]

I fired up my boat in the driveway this weekend after 5+ years of no run... heard a clatter or knock from jet area. Only while engine is at idle. If I rev engine sound goes away. (Stopped engine to investigate) I have disconnected the engine from the jet and pulled the motor. If I grab the end of the input shaft (to the jet) and wiggle it back and forth (clockwise then counterclockwise) I hear a little knock. I think this might be the impeller loose on the key???

I opened up the inlet access port and there are no dead squirrels or other flotsam inside the intake area and front of impeller blades look OK.

What do you think it is?

Also, how much axial play (in direction of axis of shaft - fore/aft) should I have when I push/pull on the input shaft??

[RLP]

if ya can get the shaft to move back in forth ya need a bearing.
go ahead and fresh that pump up,well worth it.if the bearing goes out it could also take ya main bearings out in engine.

[speedboats]

Are you running a stainless impellor? They are notorious for 'rattling' at either idle or just above idle. Take the impellor away for a balance, also check all the blades are the same length (seems strange but I've seen this once before). If it is the impellor it won't hurt the unit so go have a good time