‘93 Echelon has prop or shaft issue

[MikeMohr]

Good morning all. Hit a damn log last weekend n bent my Acme 515. Took it to a local shop and he did a good job with the blocks and thought the shaft was ok. But when I tested yesterday I can feel a high frequency vibration that varies up to 3000 rpm - That’s new!  Above 3000 it just growls and you feel nothing for acceleration - That sucks! My prop doesn’t seem right and should probably put a dial indicator on the shaft ahead of the brace. What’s my shaft runout limit? And where can I gat a shop manual and a new 1 1/8” shaft if I need one?

 Oh and I went shopping and bought a new 515, puller and hardware kit. Thoughts?

[Woodski]

I don't recall the specific spec. although anything more than .003" - .005" would lead me to have it straightened.  When you check, make sure you check at the prop mounting end also, good chance a bend occurred past the cutlass bearings to the tail.  A hard hit may also have created an engine alignment concern, worth checking that also which could lead to the symptoms you are describing.  Does the problem happen with the old prop (repaired) or the new one?

[MikeMohr]

Thanks @Woodski  This is happening with the repaired prop. New one hasn’t arrived yet. 

Found the tech library posted this morning... need to figure out what gearbox I have and see if there’s shaft removal in a tech manual there. Engine alignment... how would one check that?  Shaft straightening is getting scarce around here (Eastern IA / Western IL). Will cross that bridge when I get there...

[MikeMohr]

Scratch that... realize the gearbox doesn’t matter so much. Found a Crew thread from Oct ‘13 from @Woodskitalking shaft removal and alignment. 

[justgary]

Also check to make sure the strut isn't bent. 

[MikeMohr]

The shaft dials out at .002 halfway between the strut and hull. .004 at the end. Plan to install the new 515 and go from there if vibration and poor traction above 3000 rpm persists. How would I check the strut?

[justgary]

The strut is mostly a visual check, but it should mostly keep the prop in front of the rudder.  It should be vertical from the hull down. 

[MikeMohr]

Good news!  Received the new Acme 515 and harmonic puller yesterday, installed and headed to test it out.  Everything is better.  No vibration anywhere in the throttle range.  Very responsive and happy with performance.  Bonus, the prop makes an audible growl when you cut the throttle - I like it!

Going back to the prop shop to offer the tech guidance that came with the new prop re: specific prop blocks to use for Acme repair.  We'll see how that goes. He did do a fine getting the old prop off, which I failed to do.

Comparing the old and new 515's side by side offers no perceptible difference visually or by feel, but the two behave very differently.  something about the shape has lost it's ability to deliver smooth thrust.

Thanks to all responders - good advice and better off for it now.

[MikeMohr]

Oh yeah, and then I slalomed behind the new 515 at almost 52 yrs old.  Used my old EP Comp2 - felt great and the boat was perfectly set with 1/2 tank of gas, only occupants were my younger son observing while my older son drove.

Dad can still do it and reminds me why I wanted this boat half my life - it's one of the best slalom ski boats ever made!