Bent Prop Shaft?

[TMcG]

I took my 23' in for annual service and winterizing a few days ago. I got a call from the shop today saying that my prop shaft is bent. It is 8 thousanths of an inch out of whack and apparently 5 thousanths is the tolerance. The prop has only a few minor nicks in it, none that would make me think that I hit something. I bought the boat about a year ago.

The possibilities are: it was bent before I bought the boat and the prop had been repaired since and it's not yet causing any problems, the yard is just trying to drum up some winter business, or it is slowly destroying my engine. I'm going in to talk to the mechanic in the morning to get a better idea of what's going on.

Any thoughts?

 

[fwebster]

This is one where I'd probably say "Show me how you measure that".

If it is .008" then you would probably feel it and would probably get some premature bearing and seal wear as a result.

 

[wreckless123]

Would they really check that on an annual maintenance inspection. That seems a little deep for just a maintenance inspection. I would guess they would need to remove the prop and with an indicator rotate the shaft to see if its bent or not. I would also guess a bad bearing could show this same situation but I dont know the insides of your outdrive.

 

[TMcG]

Just talked with the mechanic and he quoated $1300 for the repair. That's a new shaft and new seals. He can't tell if the needle bearing needs to be replaced until the shaft is out. I'm not seeing how I have much of a choice. I don't want to end up replacing the entire lower unit next season.

Also, I was quoted $500 for winterizing. Now I'm told that will come to around $1000 because he had to remove all of the aft seats to be able to get access to the drain plugs. I had a water pump replaced last year along with some other service and I don't remember hearing about an access problem with this engine compartment.

This is Cap Sante Marine, a well-respected yard in Anacortes north of Seattle.

 

[Sundancer]

Moving the aft seats to get to the drain plug? Something seems amiss there. If they quoted that amount, they should have called to let you know FIRST! If you can see the motor, you can easily wrap your arms around it to get to the drain plugs. I'd question that one big time! Is you boat different from any other boat? I doubt it!

 

[Chatuge]

Hmm access is tight in there - I used to have a similar engine layout to you, but you can get down the side and slowly inch in there to get to it. It is possible without taking out the seats though.

 

[BonBini]

Sounds to me like 1): you've been running this bent shaft and hadn’t noticed it. 2): something happened last time out or when moving the boat around.

Based on the tolerances given your 0.003 out of spec. I seriously doubt anything inside the lower unit is bent, just some observed runout of the outer portion of the output shaft. Also there is bearing clearance to be considered. If the shaft runout was measured in a way to include bearing clearance... well as mentioned above "how was the shaft measured"

Ask this mechanic how much metal was found on the drain plug when the unit was serviced. That will be a indicator of the drives internal health. Also ask how often they come across this and what the consequences will be by running the unit as is.

BTW... update you sig to include what outdrive you have. ...Ron