Mid-RPM range vibration issues

[danond]

I have an off-idle vibration issue, I can't recall the RPM, but it's just before I plane. It changes slightly in a hard turn and goes away once we hit around 15+ mph.

I just had the engine out and re-installed it, then aligned it with an alignment tool 'till it was dead on. The vibration was there before I pulled the engine.

I had the u-joints replaced last year and greased them this year - they looked perfect (less than 20 hours on them). The prop looks excellent, not a single ding, but my skag does have a twist to it, looks like the previous owner backed into something and tweaked it. Not enough to gouge it, but its definitely twisted.

Drive doesn't leak, doesn't make weird noises, prop doesn't wobble when I spin it by hand.

What are some areas I can look into? Is it possible my prop was repaired incorrectly at some point?

 

[BAYLINER185]

Re: Mid-RPM range vibration issues

well you had the motor out........How was the gymbal bearing?

I had a bad vibration and it slowly got worse before the bearing wouldnt turn any more.

 

[danond]

Re: Mid-RPM range vibration issues

Sorry, should've said - gimbal was replaced last year, too. Less than 20 hours on it.

 

[fuzzybob]

Re: Mid-RPM range vibration issues

Have you looked at the rotating stuff on the front of the engine? Pulleys, power steering pump, water pump, harmonic balancer?

 

[danond]

Re: Mid-RPM range vibration issues

I've watched them while the engine is idling, never when going any faster than that. I'll take a look at those.

This being my first I/O, is there any acceptable level of vibration from the engine? Meaning, do some engine and engine mount combinations tend to produce more/less vibration than others?