HUNTER 40 1986 WITH BAD SHAFT VERIBATION

Jun 3, 2004
11
Hunter 40 mears great oak
I HAVE REPLACED THE SHAFT WITH NEW HIGH TENSILE S/S SHAFT.
REPLACE THE CUTLASS BEARING, HAD THE STRUT CHECK AND TUNE, THE SHAFT SHOP SAID NOTHING WRONG WITH IT. CHECK THE MATER MOUNTS THEY ARE GOOD REPLACE IN 2000. ALIGN THE COUPLING FOR SHAFT TO MOTOR IN WATER. IF I RUN THE MOTOR ABOVE 1700 RPM GET VERY BAD VIBRATION ON BOAT CAN NOT GO ABOVE 5 MPH.

ANYBODY HAVE OTHER IDEAS?
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
Have you balanced the prop??? Also change the zinc it may have a void on one side

Les
 

SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Beyond the prop -- which is a question.
What's the coupling like? Vibration isolator?
The motor mounts -- why do you say, 16 year old motor mounts are necessarily okay?
Does it do this in reverse as in forward?
Have you looked at the engine while this "very bad vibration" is happening?
 
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
Check for runout in the shaft. If none is present, then look at the prop. If you don't see an obvious prop problem that you can fix yourself, then take the prop off & see if the shaft still vibrates. Rock the motor around by hand as hard as you can & see how much it moves. Feel for play in the coupling. If you haven't found anything yet, then take the prop to a prop shop & have them inspect it.
 
Jun 3, 2004
11
Hunter 40 mears great oak
Had a good pro shop balance it
Beyond the prop -- which is a question.
What's the coupling like? Vibration isolator?
The motor mounts -- why do you say, 16 year old motor mounts are necessarily okay?
Does it do this in reverse as in forward?
Have you looked at the engine while this "very bad vibration" is happening?
had prop balance
took a large bar and try to move motor mounts, they are good no movement
Yes it vibrates in reverse
was at the engine under load wile running at 2200 rpm no motor movement
Do not have vibration isolator but never did be
 
Jun 3, 2004
11
Hunter 40 mears great oak
had prop balance
took a large bar and try to move motor mounts, they are good no movement
Yes it vibrates in reverse
was at the engine under load wile running at 2200 rpm no motor movement
Do not have vibration isolator but never did before this problem started
 
Jan 25, 2018
23
Catalina 30 Bristol
Is it a folding prop? some times mine on the Catalina 30 will not open it causes a vibration. I have to shift from forward to reverse then back to forward. Im with a previous commitment, remove the prop and run the motor in gear.
 
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Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
@85bittersweet you May never know the answer. The post is from 2018. The original poster has not replied to this thread since 2018. And his last time on the site was 13 months ago.

Your suggestion was a good idea to try and isolate the problem.
 
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