Broken woodruff key!

[Emptytemples]

Hoping for some help from all of you experienced jet boat owners. Hopefully but unfortunately this happened to someone else so I can get a better idea of costs (labor hours, parts that may have to be replaced, issues that might arise, etc)

We were in Ocean City, MD this past weekend as usual when all of the sudden the engine cut out when we were under power. out plug, pulled the bag I tried starting again. It sounded like the starter was working but not engaging the starter gear and cranking the engine over. At first, I assumed it was something that happened to the starter. After further investigation the next day, exhaust manifold off, starter off and jumped to check if it was working properly.
Once we figured out how this starter works, we knew it was functioning. After some more troubleshooting, we realized the pump was spinning but the engine wasn't cranking, we looked at engine diagram. It seems that the key between the crankshaft and starter gear broke when I sucked up the bag.
My options are to do the work myself, make and buy the tools needed hope I don't run into bigger problems down the road.
Take the boat to a dealer and let them pull the engine and replace the key since they are better equipped.
Or pull the engine before giving it to the dealer since it will save some time and most likely money.


Has this key broken on anyone before? I'm looking to see what problems came up if any when replacing this piece. Everyone was closed today for the holiday so I couldn't get estimates. Looking for any feedback or advice.

 

[Zizzou 192]

Have not dealt with this on a boat engine, but the concepts are similar on all engines with a stator.

Basically the woodruff key is usually a tiny 50 cent piece of half moon shaped pot metal that is meant to shear. The big problem is when it makes the divot in the crankshaft larger than it should be that it sits in, future woodruff keys will continue to shear until you replace the crankshaft.

Hopefully the slot / divot in the crankshaft will not be enlarged so you won’t have to tear the motor apart.

So when you torque the stator nut back on make sure it is to the correct torque value.

 

[Scottintexas]

How does pump spin but then engine doesn't turn?? By pump I'm guessing you mean the impeller

 

[Emptytemples]

How does pump spin but then engine doesn't turn?? By pump I'm guessing you mean the impeller

Well that's what I believe the woodruff keys sole purpose is. There is essentially nothing what to protect the engine since it is direct drive?

 

[Emptytemples]

Have not dealt with this on a boat engine, but the concepts are similar on all engines with a stator.

Basically the woodruff key is usually a tiny 50 cent piece of half moon shaped pot metal that is meant to shear. The big problem is when it makes the divot in the crankshaft larger than it should be that it sits in, future woodruff keys will continue to shear until you replace the crankshaft.

Hopefully the slot / divot in the crankshaft will not be enlarged so you won’t have to tear the motor apart.

So when you torque the stator nut back on make sure it is to the correct torque value.

Was thinking the same thing and hoping the same. Really hoping the key sheer was precise. Was also hoping that a piece of the key didn't Mar the crankshaft while/ if it spun.

 

[Emptytemples]

Update. Most likely was a broken timing chain. Bayside jet drive said it is a known issue with these era timing chains. He said most likely no damage to bottom end and would just have to replace top end and components. Luckily comprehensive insurance covers this or I'd be looking at anywhere between 4500 and 10k. They did say they would try to get some good will from Yamaha since it is a known issue but we'll see what happens since I'm going through insurance.

They did say as well that the broken woodruff key between the starter gear and crankshaft are very uncommon. Obviously they wouldn't know exactly until the engine is pulled out and taken apart. The estimate was 10 ish hours of labor for top end only. Hoping I can get it there in the next few days and parts are in stock to get another few boat days in this year. Bottom ends are 7 to 8 weeks out i believe so that would nix the season. Will keep anyone posted if interested. Enjoy the rest of the season if you are north of the Carolinas!

 

[Zizzou 192]

!

Lots of threads on here on pre 2017 timing chain failure and even one on how to read your engine build date on the underside of that nice plastic engine decorative cover.

Need to read over my boat insurance policy. I have already consciously modified my boat piloting habits to minimize pump unloading in the rough and cut out rapid decelerations after reading too much on this subject. 2015 SX 192.

What year is the boat?

 

[Emptytemples]

!

Lots of threads on here on pre 2017 timing chain failure and even one on how to read your engine build date on the underside of that nice plastic engine decorative cover.

Need to read over my boat insurance policy. I have already consciously modified my boat piloting habits to minimize pump unloading in the rough and cut out rapid decelerations after reading too much on this subject. 2015 SX 192.

What year is the boat?

2014 sx. I had no idea and haven't caught those posts but will definitely read up on that. I'm not one to rapidly decel in any boat to mitigate water into cowls, over swim platforms, for general comfort but definitely never consciously for a timing chain issue! Thanks for that tip and will research as soon as I get back on a laptop. Love the forum but it's been a pain typing and researching on my phone. First world problems... boats and phones