damaged prop

[stp119]

I bottomed out and damaged my prop pretty bad. I have an I/O Bayliner, Merc engine. Can I just take the prop off and replace it or is there something else I should be concerned with? Thanks, Steve

 

[f_inscreenname]

Re: damaged prop

Unless the drive is leaking put a new prop on it and give it a try. Most props have a rubber ring inside of them designed to come apart if the blades impact something. Saving the outdrive from having shaft damage. Not saying it always works but it does most of the time. Cross your fingers and don't go to far from the dock without shaking it out.

 

[Boomyal]

Re: damaged prop

Install your new or repaired prop, start the engine(with muffs of course) engage forward and watch for any wobble which could indicate a bent propeller shaft. If it looks ok, be sensitive next time you launch for any wobble in the steering below planing speed. That could indicate a bent prop shaft that was not evident visually.

 

[Rickles]

Re: damaged prop

I've seen aluminum props take a hard hit with no serious damage to the prop shaft.If you have a stainless steel prop have the shaft dialed(prop shaft run-out)to be safe.You're only alowed .008 run out.If it's bad and not repaired you have a good chance of water intrusion to the gear case.this will cost big $$$if not caught in time.Don't take a chance get it check out.

 

[ob]

Re: damaged prop

Rickles offers sound advice.Whether your prop is repairable or in neede of replacement,make doubly sure that you have performed a rolling runout using a dial indicator of the propshaft to insure it's not bent.<br /><br />He's a bit more lenient on the runout tolerances than me.

 

[navigator336]

Re: damaged prop

You can check the run-out reasonably accurately yourself even if you don't have a dial indicator. Take the prop off, put the nut back on. Lower the drive and clamp a heavy steel "L" bracket (from Home Depot, etc.) to the anti-cavitation plate. Screw a small "L" bracket at 90 degrees to the big bracket on the other end. Now loosely clamp a stainless steel ruler or heavy piece of wire, etc.(the indicator) to the small "L" bracket and adjust it so the end of the "indicator" just touches the prop shaft at the prop nut end of the shaft and clamp it tight. Now slowly rotate the prop shaft and observe if a gap develops or it gets tight. If it gets tight readjust the "indicator" so that it just touches. Keep rotating and adjusting until the indicator is positioned to touch the shaft only at the shafts maximum excursion off centerline towards the indicator. Finally, rotate the shaft until the maximum gap develops. Use a feeler gauge or sheets of notebook paper (approx. 0.004" per sheet) to measure the gap. This gap will be the total run-out. The run-out is half this.