Prop shaft run out specs?

[jopes]

I seen this thread with a video and was wondering what the limit is? The video says anything more than .002" will cause vibrations.

http://forums.iboats.com/prop-questions-topics/how-you-measure-prop-shaft-runout-363521.html


Ever since I bought the boat 3 years ago it has vibrated. Tried multiple props, had the lower unit off more times than I care for to be sure the coupler is aligned properly. New u-joints on the input shaft. Nothing has changed. I measured in multiple places and I am going to say after the nut I am seeing .005-.006" on the dial indicator.

So the question is, Do I need a new shaft?

 

[Bondo]

Re: Prop shaft run out specs?

I seen this thread with a video and was wondering what the limit is? The video says anything more than .002" will cause vibrations.

http://forums.iboats.com/prop-questions-topics/how-you-measure-prop-shaft-runout-363521.html


Ever since I bought the boat 3 years ago it has vibrated. Tried multiple props, had the lower unit off more times than I care for to be sure the coupler is aligned properly. New u-joints on the input shaft. Nothing has changed. I measured in multiple places and I am going to say after the nut I am seeing .005-.006" on the dial indicator.

So the question is, Do I need a new shaft?

Ayuh,.... My rule of thumb has always been, If I can See wobble in the end of the prop shaft, it's Bent, 'n needs fixin',...

Donno the Spec, off hand, but that number sounds reasonable, 'n yer's is twice to 3 times that,...

 

[achris]

Re: Prop shaft run out specs?

Book spec is 5 thou for replacement. I have successfully straightened a bent shaft... I think it was about 10 thou out. Using a press and a couple of vee blocks, I was able to get it to within 2 thou.. So it can be done...

Chris......

 

[jopes]

Re: Prop shaft run out specs?

Bondo, so you just put it in gear with the engine idling to check that? spinning it by hand I cannot see a wobble in it.

 

[Bondo]

Re: Prop shaft run out specs?

Bondo, so you just put it in gear with the engine idling to check that? spinning it by hand I cannot see a wobble in it.

Nope,... I kneel down to it, hold an object from a solid point to the center of the prop shaft, 'n turn it with my fingers,....

Ya need a solid point projected to the shaft center,...