Vibration, alignment problems

[Mitchel Stroh]

I recently purchased a 93 Hunter 33.5. The boat was in dry dock at the time of purchase so no sea trial was done. When the boat was delivered and launched I noticed a strong vibration around 2700 to 2800 RPM. I had an alignment done but the engine mount was such that it left the alignment off by about .008 of an inch. The vibration is less but still seems too strong to me. While looking through my new West Marine catalog I notice a new device called a Divesaver. It claims to reduce vibration by 70 to 80%. Has anyone used one of these and if so what was the result.

 

[SteveC]

I have a drivesaver

installed on my 37 and it does reduce vibration somewhat but the main reason I installed one was to electrically isolate the shaft/prop. Things you should check(not in any particular order) are: is shaft/prop free of all growth, are motor mounts ok(not causing engine to jump around excessively), is propshaft true, is cutlass bearing OK(no play when wiggled), zincs not corroded excessively and engine alligned to propshaft both vertically and horizontally. I''ve had all of the above(except bent propshaft so far - knock on wood) and they all caused some sort of vibration at one time or other..

 

[Sam Lust]

Bad Vibes

You failed to state what engine you have but no matter. If your alignment is out .008" you're not even close to the ballpark. I align my engine so I can't get a .0015 feeler in anywhere around the coupling falnge mating surface. (That's one and a half thousandths of an inch, not eight thousandths.) If your mounts are shot they've got to be replaced.The drill is: Replace mounts, have prop trued, check shaft straightness, replace cutless bearing, align. Your vibes won't get any better.

 

[Andy Falls]

Good Vibrations

MITCH! where have ya been! Where did you get that bucket? Boat tradin' fun ehe? I've heard that the hull can miss-align the shaft as it dries up. I'll bet a little feeler gauge adjustment will straighten her up. Send me an email, I in the owner's log. If there is(are) an answer(s), you will find them at HOW