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foxfury

  • Karma: +0/-0
vibration
« on: June 01, 2011, 06:18:13 AM »
I have a vibration somewhere either in my engine or dominator drive I can't pinpoint.  I pulled the motor to check the thrust bearing but it seems tight with no side to side play.  What are the possibilities that I have an out of balance flywheel/harmonic balancer, or could it still be the thrust bearing? 
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crewchief22

  • Karma: +66/-0
Re: vibration
« Reply #1 on: June 01, 2011, 06:42:13 AM »
Have you verified that there isn't a rock in the impeller?

If you have the engine out, spin the pump by hand and see if there is any roughness in the bearing.  My WJ had a growl noise when running but once apart had a noticeable rough front bearing.
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  • Boat #1: '77 Hondo Pantera GT Jet
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GT Jets

  • Karma: +192/-0
Re: vibration
« Reply #2 on: June 01, 2011, 09:24:06 AM »
Has it ever been smooth? could be an alignment problem....

GT
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  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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Quote from: Brad @ SoCalJetBoats.com on December 22, 2009, 07:40:31 PM
If i get some free time tonight at work, ill play with it and post it for everyone to see.

Quote from: IRRebel on June 11, 2011, 07:30:45 PM
Time to man up and yank it John!  :banghead:
Ray

TIMINATOR

  • Karma: +5/-0
Re: vibration
« Reply #3 on: June 01, 2011, 01:16:44 PM »
What brand motor? Have you checked to see if somthing is stuck in the pump? Cam going flat? Bad plug wire? We need more info.  TIMINATOR
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foxfury

  • Karma: +0/-0
Re: vibration
« Reply #4 on: June 01, 2011, 08:17:08 PM »
motor is a 454.  the shaft spins freely with no rough spots or tightness.  I ran the motor today and have a noticeable vibration.  Gonna change out plugs/wires and have the flywheel checked.
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GT Jets

  • Karma: +192/-0
Re: vibration
« Reply #5 on: June 01, 2011, 09:23:10 PM »
Quote from: foxfury on June 01, 2011, 08:17:08 PM
motor is a 454.  the shaft spins freely with no rough spots or tightness.  I ran the motor today and have a noticeable vibration.  Gonna change out plugs/wires and have the flywheel checked.


A miss is definitely different from a vibration......Has it ever run smoothly since you have owned it? (He says again with a little irritation in his voice)  :D

An incorrect harmonic balancer can do what you describe, of course so could a thrown rod. :-\

GT
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  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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Quote from: Brad @ SoCalJetBoats.com on December 22, 2009, 07:40:31 PM
If i get some free time tonight at work, ill play with it and post it for everyone to see.

Quote from: IRRebel on June 11, 2011, 07:30:45 PM
Time to man up and yank it John!  :banghead:
Ray

76 Bonneville

  • Karma: +25/-0
Re: vibration
« Reply #6 on: June 01, 2011, 09:44:02 PM »
I hate to admit it, but I once put the flex plate on backwards.
I thought it was going to rip the stringers out.
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GT Jets

  • Karma: +192/-0
Re: vibration
« Reply #7 on: June 01, 2011, 09:49:41 PM »
Quote from: 76 Bonneville on June 01, 2011, 09:44:02 PM
I hate to admit it, but I once put the flex plate on backwards.
I thought it was going to rip the stringers out.

The flexplate was on my jet backward when I bought it, he actually thought the crank was broken... :D

GT
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  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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Quote from: Brad @ SoCalJetBoats.com on December 22, 2009, 07:40:31 PM
If i get some free time tonight at work, ill play with it and post it for everyone to see.

Quote from: IRRebel on June 11, 2011, 07:30:45 PM
Time to man up and yank it John!  :banghead:
Ray

76 Bonneville

  • Karma: +25/-0
Re: vibration
« Reply #8 on: June 01, 2011, 09:54:35 PM »
Quote from: GT Jets on June 01, 2011, 09:49:41 PM
The flexplate was on my jet backward when I bought it, he actually thought the crank was broken... :D

GT
I flipped the flex plate around after a weekend at the river. Ran it the rest of the season, even a trip to Powell. Tore it down in the fall and found a cracked crank.
Thats why I stick cabinets.
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lbhsbz

  • Karma: +29/-1
vibration
« Reply #9 on: June 01, 2011, 10:29:06 PM »
Make sure that you've got the right flexplate/balancer to go with your crank.  Stock cranks ate externally balanced....use offset balanced end pieces.  Some aftermarket cranks are internally balanced and use neutral balanced end pieces
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jet boat performance

  • Karma: +25/-0
Re: vibration
« Reply #10 on: June 02, 2011, 08:22:36 PM »
Quote from: foxfury on June 01, 2011, 06:18:13 AM
I have a vibration somewhere either in my engine or dominator drive I can't pinpoint.  I pulled the motor to check the thrust bearing but it seems tight with no side to side play.  What are the possibilities that I have an out of balance flywheel/harmonic balancer, or could it still be the thrust bearing?

Just curious , is this a vibration you can feel ? and does it change or get worse/better with RPMs or is it a "stacato" noise you can hear (very iomportant!) Also may have missed this but is this new and has anything else changed or been changed Tom
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foxfury

  • Karma: +0/-0
Re: vibration
« Reply #11 on: June 06, 2011, 04:30:01 AM »
Not sure if the motor has ever run smooth.  I bought the thing gutted and just recently fired up the motor.  I can definetly feel the vibration and it speeds up when I rev the engine.  No noise other than the rattle created (not in the engine).  Im gonna change out the cap, wires and plugs and see what happens.  IF IT EVER STOPS RAINING!  thanks for all your help guys. ;D
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foxfury

  • Karma: +0/-0
Re: vibration
« Reply #12 on: July 05, 2011, 05:50:59 PM »
Turns out it was the harmonic balancer.  boat runs like a top now.
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