pump problems

[MellowYelloW]

Well i finally got my boat in the water...ran really good. but today i was going for a ride and started hearing this grinding sound coming from the pump i think. any one have any idea what would cause this..the pump was just rebuilt. only the second day out on it. please help!!
berkely 12-jg pump

[spectras only]

Mellow, I suspect a few things.#1: the impeller /sholder wear ring forward clearance was set too close and some forward movement of the shaft happened, and the impeller touching the wear ring.#2 an inferior thrust bearing was installed and failed [may not have been lubricated properly prior to run the boat in the water].I've seen bearings with plastic ball cages and less balls [very bad practice]that failed prematurely.#3 the thrust bearing cap wasn't checked for keeping the bearing from axial movement toward the engine by the thrust of the impeller and the bearing may have travelled far enough forward to cause the impeller grinding into the wear ring.The early berkeley's didn't have a shouldered ring so it wasn't an immediate problem with minor movement.I'm sorry to say ,but the bowl and impeller would have to be removed to further investigate the problem.If you didn't do the pump yourself,it definetely should be checked under warranty.

[rstover1]

Mellow I had a berkeley 12 je rebuilt and the guy who did it here in Ok. didn't properly adjust the packing at higher rpms water washed all the grease out of the front bearing with no grease it sounded terrible a new bearing and grease and packing adjustment fixed it. Do like I did take it back to whoever rebuilt it if its a shop Im sure they wont want an un happy jetter to deal with

[froggystyle]

Could be a small gnome living in the bowl section too. That happens if you don't cover the intake when you are towing http://free.***boat.net/ubb/wink.gif

[spectras only]

rstover1 ,there are two seals on the shaft to protect the thrust bearing from water.You must maintain a check to see if excessive water coming trough the packing gland.You can have one drop per minute while the engine turns to help lubricate the shaft and the packing.You must have had a flash flood going trough to wash the bearing grease out of a sealed unit!When a reputable builder finished a jet rebuild, normally makes an information sheet what to do during the first running.

[MellowYelloW]

hey guys thanks alot...i took it to the guy who built it, actually his partner and they said that it is normal shaft vibration when the pump is not under load. he said that it is totally normal..what a releif!!
thanks again

[HBjet]

Mellow, just curious, who did you take your pump to? When I had my pump rebuilt and blue printed I never had a grinding sound coming from it. Personally I would question the diagnosis of normal shaft vibration, since you said you started to hear the sound sometime after you were going for a ride, wouldn't that be under a load?. I would get a second opinion.
HBjet

[spectras only]

Mellow,don't get brainwashed! What they ment is ,that's ok if you get a rattle without loading the impeller [ie http://free.***boat.net/ubb/redface.gifut of water]because you may have a slight play in the yoke that couples the pumpshaft to the velocity joint.Once you have the boat in the water,even at idle you shouldn't have a rattle.It's not defined in your post if you have a rattle or a vibration.Vibration would come from either a bad alignment,bent shaft or an out of balance impeller.

[Bubbledeck]

I got hosed on my pump rebuild (long story), but it doesn't and has never made a grinding sound or had a vibration in it ... well, unless you count the time an intake finger went through it heh.
I think you should explain things to your pump builder so he can understand a little more clearly. I'd try the direct approach like " hey, you're gonna look awfully funny with a grinding Berkely pump sticking out of your ass" This may get his attention and give him incentive to investigate the noise further :-)

[timitunnel]

I have never seen a methane powered jet boat.
Maybe if someone built one it would get the nature natzi's off our backs for awhile!