Propshaft Runout
 

Back on Labor Day weekend I struck something (due to low water levels). The prop suffered pretty major damage and is being sent off to BBlades for rework. With the damage to the prop I assumed there would be prop shaft damage as well. To get through the Labor day weekend, I heated the prop up and beat it back into a usable shape.. much to my surprise, there wasn't much vibration and the boat performed rather well.... The boat hasn't been used since..... I pulled the boat out of storage today and measured the runout on the prop shaft. I measured a total of .010" of runout. While .010" isn't that much, I assume it is too much for a prop shaft....... So my question is, what is an acceptable amount of run out for a Bravo 1 prop shaft?

The lower unit on my boat is an SEI unit and it has a 3 year no questions asked damage warranty so I plan to send it in. However, I don't want to send it in of .010" is within tolerance (I am guessing its not...)

Send it back, that is too much runout. .005 if memory serves is the max permissible.

I have seen new merc prop shafts as bad as .007..i like to see a max of .003 but you take what you get when it come out of a new cylinder..

Quite frankly if the splines were straight and I owned the lower with no warrantee, I'd give it a whack with a dead blow to get it under .005. Been there, done that, worked just fine. It is twist in propshaft splines that make them weak.

Spines are straight. I was at idle when I struck what ever it was. It actually shut the boat off...... If the lower wasn't covered by a no questions asked warranty, I would probably take a shot at straightening it.... But since it is, all I have to do is pay shipping to get it replaced.

whats the harm in trying the hammer trick,if you make it worse,send it in,if you make it better,go boating.

It is freezing cold still here in MI. The lower has a three year warranty that began may, 3years ago... since the season has not started here in MI yet, no sense in not using this time to send the drive in.... The more I think about it, with as much damage as my prop saw, there may be more hidden damage inside the lower..........

You were at idle and did all that damage?

Yup. I am guessing it was a big freaking rock. What probably saved more damage to the drive is the fact that I am running a labbed prop. Had it not been labbed (thinned) I would guess the drive would have suffered more damage. The prop ended up with one blade folded over about 3" in from the tip. Another blade suffered a very large gouge.

I have some pics of the prop damage, I will try and dig them up in the morning.