WTF Happened and How Much is this Going to Cost to Fix

[1Cast 1Fish]

Not real sure what I am looking at, but it looks bad to me...lol. I was going through the boat and doing my normal new year maintenance and found the prop was loose...upon further investigation I found the nut was only hand tight. The cotter pin and everything was still in place, so I took everything apart and found this mess on the thrust washer. I have no idea what or how this could happen. I never hit anything with the prop, or did anything that would be a cause for concern...I have no idea how long it was like this either since I never felt or heard any vibration or performance loss. Can someone with a clue chime in please.

2014 ETEC 150
Merc Tempest Plus Prop

Prop1.jpgProp2.jpgProp 3.jpgProp 4.jpg

[bighare]

The damage is called fretting and galling. The damage occurs from an under-torqued prop nut. Torque must be 80 ft lbs.
I also notice the thrust washer is not an Evinrude type but rather the thrust washer for your Merc prop. There is different alloy between the merc version and the Evinrude version. These alloy differences were contributing to the galling and fretting of the taper of the prop shaft.
This wear is now a major weak point for potential breakage / eventual breaking of the prop shaft.

[mactlman]

insurance will cover that damage from hitting the stump!!

[ChampioNman]

As bighare says prop nut not torqued to spec. I do see a lack of Triple Guard grease on the prop shaft. It should clean up OK but if you feel the need to have the drive shaft replaced depending on your model number MSRP is $390.99 and figure two hours labor for the replacement.

[blkfalc4]

Answered in the Lounge topics to your question.

If the thrust washer was installed as you say with flat side toward gearcase, then it was installed backwards.
Flatside is for the prop base to sit against.

[1Cast 1Fish]

As bighare says prop nut not torqued to spec. I do see a lack of Triple Guard grease on the prop shaft. It should clean up OK but if you feel the need to have the drive shaft replaced depending on your model number MSRP is $390.99 and figure two hours labor for the replacement.

I have received a ton of help and some great ideas from everyone on here, so thank you. It had no grease hardly because I cleaned it up for pics and see the damage better.
I am going to try a wire brush, then emery cloth, then scotch bright to clean op the surfaces and see what we got.

[Rips LEGEND]

I had a 200hp etec small block like yours. With Mercury prop hub kits the plastic sleeve would melt from the exhaust heat. I had it happen every time to the point I changed back to a Raker prop. look at the sleeve and you'll see what I mean. I've got an HO now and it doesn't happen.

[tdt91]

I have suggested to BRP users for years that if they are going to use a Mercury prop (I do) then it's best to use the Michigan wheel hub kit #200 for the Etec G1 V6 engines.
The Merc hub kits squish and get to the point that you cannot tighten the nut enough because it bottoms out on the not threaded area of the shaft. The thrust washer ends up spinning on the prop shaft and causing what you see in the photo's. It has happened to many guys and you are lucky you didn't lose your prop out in the water.
Replace the prop shaft and use a MW #200 hub kit if you continue to use the Merc prop.
All the other stuff about what caused this is just speculation. Fortunately I started researching when I noticed the issue starting with mine and that I could not tighten it enough because it bottomed out. It was this forum were I learned what I have just explained here. I have used the Michigan wheel hub kit for several years now and have had no issues.

[1Cast 1Fish]

I got everything cleaned up, but the shaft is scored and the taper ate up a bit. Looks like I will be calling around for a new prop shaft install.