2017 250 SHO Won’t ‘Go’...Help Me Diagnose the Problem

[brianf.]

OK, my boat is sitting on the boat lift after having a major malfunction this morning. Cruising down the lake in 40 feet of water at about 45mph the boat suddenly lurched to a stop. The engine was running but the boat shut down as if I had blown the motor. Turns out the prop wouldn’t spin and would sit there as if in neutral despite giving it the throttle. Won’t go in F or R. Initially, I figured I had spun the hub, but now think my transmission gearing took a dump since the hub kit was so firmly seated in the prop once I got back to the dock and took it off (have a 8hp kicker that got me home). Heck, I couldn’t even pound it out to replace it. Plus, the one and only time I actually spun a hub before the motor would go into both F and R, but just not very fast.

Am I as screwed as I think??

[bgibson]

Sounds like the lower unit seized up

[bkeenom]

From your description I don't understand what the motor is actually doing. Are you saying the motor runs fine but will not spin the prop when you were in forward or reverse or is everything completely locked up and will not move

[brianf.]

The engine runs but the prop won’t spin. :(

[Ranger-85]

Pull lower drain plug see if any oil ??????

[brianf.]

Gears seized. Needs a new lower unit. Got one on order. $4800. Parts back ordered due to COVID shutdown. Let’s hope Yamaha comes through quickly.

[Tx Champ]

Not rebuildable?

[brianf.]

Apparently not rebuildable.

[brianf.]

Update: Before sending a new lower unit, Yamaha wanted my mechanic to tear down the failed lower unit, send a download from the engine computer, and send pictures of the lower unit inside and out...just to be sure I didn’t hit something. I was there when my mechanic took it apart. Turns out the drive shaft broke in half...not on the thin end up in the motor but in the thick part down in the lower unit. The bearings were damaged as well as the housing. It was ugly and smelly (lower unit oil burned?)...kinda like us fishermen. Fortunately, Yamaha agreed to cover the replacement under my 6 year warranty. Just waiting on parts to come in now. Hopefully, the ordeal will be over n a couple weeks.

[brianf.]

Final Update: The new lower unit was installed yesterday...a 5+ week wait thanks to covid supply chain disruption. At least Yamaha made good on the warranty. All is well again.

[BigDozer66]

Final Update: The new lower unit was installed yesterday...a 5+ week wait thanks to covid supply chain disruption. At least Yamaha made good on the warranty. All is well again.