Prop shaft runout

[Sea Ox]

I was replacing the prop on my BF130a and the prop shaft had visible runout. I rigged up a dial indicator and it showed .040" runout on the smooth part of the shaft between the spline and the threads. It dosen't sound like a lot, but it looks like a lot. There is not noticeable vibration when I'm running, but my previous boat was and older 2 stroke, so my point of reference may be off. I can't find a spec for allowable runout of the shaft in the service manual. What would that be?

 

[dinghyworld]

Hi Sea Ox,

There is not a specification for run out due to the fact that no run out is good, any is bad. With the amount you have I would be replacing the shaft to save issues with water in gearcase at a later time. It is amasing how little run out it takes to allow water to get into the box. You wont feel vibration as it is lost in the transfer to the engine and the transom clamps.
Good luck with the repair

cheers
John

 

[jgmo]

I vote with dinghyworld. I've never actually measured it, but .040" sounds like a bunch. I would expect to see more on the order of less than .005".