Mr1 trashed. What next?

[spatty99]

I'm pretty sure that is my old boat. Bummed and sorry to hear about the engine. A little history from what I can remember...
I bought it maybe a few years old with 40 something hours. Around 100 hours the port engine blew a rod. Supposedly a Yamaha engineer happened to be visiting the dealer and said it was just a freak failure. I had the Yamaha dealer replace the engine using an SBT rebuild. It ran flawlessly for the next 200+ hours. I even had oil analysis done every oil change after the rebuild, and numbers looked even better than the factory engine. It was only in salt a couple times but promptly rinsed/flushed, otherwise was 99.999% freshwater. Maintenance was always done per the manual.

 

[Seedogg]

@itsdgm Thanks! I do not plan to use SBT internals if I get to rebuild it myself. I am not sure what was rebuilt previously, but I doubt SBT had anything to do with the valves. It is looking like that was the failure, so I can't really place any blame on them.

@WREKS I did recover 1 spring lock in a crevice of the head. I also recovered the shim near the other exhaust valve, and about 75% of the lifter surface. The skirt of the lifter remained intact and dropped around the spring.

So, you think, valve spring broke leaving valve open, spring lock drops in cylinder, beats around until piston falls apart, piston launched past TDC hitting and bending open intake valve and striking plug electrode?

 

[Seedogg]

@spatty99 Yep, that is it. No complaints at all here. We have had 2 great seasons with it. Oil analysis both seasons were great as well. Just bad luck.

 

[WREKS]

@Seedogg Or Valve spring breaks allowing spring locks to loosen from valve stem, allowing valve stem to drop below spring seat, allowing spring lock(s) dropping into spring seat to get between top of valve stem and spacer so that when piston returns to TDC it hits the open valve whose stem jams the lifter into the rotating cam breaking the lifter and the piston at the same time. Or something like that.

 

[Seedogg]

@WREKS I figured something had to drop in to the cylinder to have beat up the head like it is. Either way, looks like broken valve spring would be the root cause.

 

[WREKS]

@Seedogg Yes. We just mentioned two iterations of 8000/60 if the event lasted 1 second. But it helps to come up with a good hypothesis in order to know how to proceed.

 

[Seedogg]

@WREKS Thank you for working through that with me. It would have taken me days of looking and thinking to come up with it.

Now....anyone have a case for sale?

 

[WREKS]

@Seedogg Thank you! Please keep updating, and questioning.

 

[the MfM]

Now....anyone have a case for sale?

The 212x is the HO engine?
I assume you’ve seen these??

FXHO 1.1L 6B6-15100-00-00 6B6-15100-00-8P

Check out the deal on FXHO 1.1L 6B6-15100-00-00 6B6-15100-00-8P at ShopSBT.com

www.shopsbt.com

I have no idea how good they are but the price is reasonable compared to eBay prices for used OEM if you can find one.

 

[14SX190]

Anyone have a different option?

I know your not close but here's a complete engine

2018 Yamaha TR1 complete engine, $2,500 no core needed 200 psi -...

2018 Yamaha TR1 complete engine, $2,500 no core needed 200 psi each cylinder

miami.craigslist.org

 

[Seedogg]

I know your not close but here's a complete engine

2018 Yamaha TR1 complete engine, $2,500 no core needed 200 psi -...

2018 Yamaha TR1 complete engine, $2,500 no core needed 200 psi each cylinder

miami.craigslist.org

Thank you for looking, but that is a TR-1. I will need an MR-1. That looks to be a very good deal on a motor though. If it were an MR-1, I would find a way to get it here. Thank you again for looking.

 

[14SX190]

Thank you for looking, but that is a TR-1. I will need an MR-1. That looks to be a very good deal on a motor though. If it were an MR-1, I would find a way to get it here. Thank you again for looking.

Oh snap.

Yeah sorry about that. If it's not the 1.8 I get cornfused....