SoCal Jet Boats

Tech Talk => Jet Pumps => Topic started by: Patch on April 28, 2010, 08:22:35 PM

Title: american turbine jet is growling?
Post by: Patch on April 28, 2010, 08:22:35 PM

I have an Advantage 20.5 classic with an ATJ-309.It is growling and when it is put into water it takes 30 seconds or so to start pumping. It has been four years since Tom Papp rebuilt it. Is it the bearing closest to the motor? Never messed with rebuilding a jet before and would like to do it myself. Any info is appreciated. Thanks Patch.

Title: Re: american turbine jet is growling?
Post by: beerjet on April 28, 2010, 08:28:11 PM

Grease the U-joints

-beerjet-

Title: Re: american turbine jet is growling?
Post by: Luckie Stiff on April 28, 2010, 08:38:53 PM

Quote from: beerjet on April 28, 2010, 08:28:11 PM

Grease the U-joints

-beerjet-

yep

Title: Re: american turbine jet is growling?
Post by: Patch on April 28, 2010, 08:52:05 PM

I grease the u-joints every other trip, along with the thrust bearing. I grease the zerk inside of the noozle after every outing.

Title: Re: american turbine jet is growling?
Post by: Patch on April 28, 2010, 08:56:10 PM

Also if I idle for to long or in a no wake zone for more than a couple of minutes the motor starts to get warm? The gate valve is all of the way open.

Title: Re: american turbine jet is growling?
Post by: beerjet on April 28, 2010, 09:55:51 PM

Quote from: Patch on April 28, 2010, 08:52:05 PM

I grease the u-joints every other trip, along with the thrust bearing. I grease the zerk inside of the noozle after every outing.

Why ???
U-joints and bearings in a car see way more water than a boats do and those dont ever get greased.
I never understood why people grease the shit outta the bearing.
Too much grease WILL over heat the bearing and cause failure WHICH COULD send the pump shaft forward and into the crank on your motor.
A bad u-joint angle can cause u-joints to make noise also.

-beerjet-

Title: Re: american turbine jet is growling?
Post by: beerjet on April 28, 2010, 10:01:12 PM

I've said it before and I'll say it again, a pump can go to shit after a single outing.
Most of the time it is caused by picking up shit on the road to the lake.
(At least this is my personal belief)
Droop Snoots are notorious for not letting the pump load upon launching.
My personal practice when launching is to let the pump fill up with water and pull it out and let it drain, then repeat.
If there is loose debris, it is more than likely gonna come out.
Thats just me though.

-beerjet-

Title: Re: american turbine jet is growling?
Post by: jet boat performance on April 29, 2010, 07:40:14 AM

Patch the "grumbling" or growling could be Ujoint/drive line noise but it typically it is prominent at idle and dissapates as soon as the impeller see's a slight load , the fact that it is getting a litttle warm and is slow on the initial "uptake" is a concern for sure and suggest some possible internal issues ,as Omar said droops are notorious for this particular problem (if equipt) and X'2 on the injestion of grime from towing etc Call Josh or myself if we can help you further diagnose this Tom

re Pump grease AT suggest a small amount added every 10 hours of operation

Title: Re: american turbine jet is growling?
Post by: 76NORDIC on April 29, 2010, 08:09:10 AM

Quote from: beerjet on April 28, 2010, 10:01:12 PM

I've said it before and I'll say it again, a pump can go to shit after a single outing.
Most of the time it is caused by picking up shit on the road to the lake.
(At least this is my personal belief)
Droop Snoots are notorious for not letting the pump load upon launching.
My personal practice when launching is to let the pump fill up with water and pull it out and let it drain, then repeat.
If there is loose debris, it is more than likely gonna come out.
Thats just me though.

-beerjet-

  X2   I do the same thing Omar :thumbup:

Title: Re: american turbine jet is growling?
Post by: Patch on April 29, 2010, 04:27:31 PM

Thanks for all of your comments. The pump is equipped with a turbine trim without a droop. Also the noise gets louder when the pump finally grabs and starts pumping. The top speed is down from 64 mph to 56 mph on a hand held GPS.  I have gotten four good years of boating on this pump since the last rebuild. Most of the time has been split between Parker and Blythe. Approx 350 hours since the rebuild.
I am going to pull the pump after this weekend. Would a droop help my advantage 20.5 classic closed bow gain more speed? Thanks for all of your help. Patch

Title: Re: american turbine jet is growling?
Post by: 76 Bonneville on April 29, 2010, 06:07:08 PM

You say you've lost mph, but have you lost or gained rpm's.

Title: Re: american turbine jet is growling?
Post by: Nordie on April 29, 2010, 06:08:22 PM

thats what i was curious about too Ron  ???

Title: Re: american turbine jet is growling?
Post by: jet boat performance on April 29, 2010, 08:26:42 PM

Droops are typically reserved (and seem to be most effective) for/in smaller lighter boats Tom

Title: Re: american turbine jet is growling?
Post by: wizard612 on June 01, 2010, 09:26:58 PM

Growling? Can't be an AT must be a Panther. But seriously get it looked at by a pro then decide if you want to fix it yourself. I would take out the u-joint and check tolerances and lub while out of the boat (replace bolts while you're at it). spin the pump by hand and feel for grit. Snug without a grind possibly ok but could be a wear ring, jiggles for and aft it's the bearing, spins like a top, wear ring maybe or it might actually be ok but probably needs lube since 90 wt will make it hard to spin. If anything feels wierd pull the bowl and inspect the impellor. Like I said have a pro look at it.