I blew up my 96 200hp Yamaha Pro-V and could use some advice

[Tiptonite]

Hello fellow BBC'ers!

First I'd like to say that I'm a long time lurker first time poster and want to thank everyone who's shared their knowledge here from which I've learned much.

A little background on my story.

2 years ago I bought a used 96 Skeeter 200zx with a Yamaha P200TLRU in excellent overall shape. For being a 23 year old motor it was very hard running. It had 105-110 compression in all the cylinders and went 65mph GPS at 6k rpms with a 25m prop on a fully loaded and fueled boat with 2 people. After buying it for $9k I sunk another $8k in upgrades and a lot of my time to get it just the way I wanted.

At the beginning of this season I did a decarb to it. Afterwards I took it out to the lake got her up on plane and once I got it above 3500rpm it overheated. So I waited till the alarm went away and limped it back to the launch. My first thought was water pump so I pulled the lower and replaced every part of it with a complete kit. Took it back out and had the exact same experience. Did some research and decided to replace the pressure control valve and thermostats. Took it back out and again it overheated. That time I noticed something odd which was air with water blowing out of the tell tale port. I also noticed during this whole thing that I started to lose top end. I did a compression test prior to decabing and all was good. I decided to do another one and this time the middle cylinder on the port side was at 80psi.

After doing some more tests, I came to the conclusion that it was a head gasket. I pulled the head and sure enough that's what it was. So I went about replacing the head gaskets and water cover gaskets. I was pretty surprised that when I took the heads off, there was no discernable ridge on the cylinders. The Inside of the motor was in amazing shape. I really couldn't believe it was 23 years old. So I got it put back together and put it on the muffs to test it. I noticed right away that it sounded and idled much better. I was stoked and couldn't wait to get it back out on the lake.

The next Saturday I took it out and started to put it through it's paces. It got up on plane faster and actually got up to 66mph. I figured done deal! I'm back in action. At the end of the day I was on my way back to the launch running at 50mph 5k rpm. My usual cruising speed. After a few minutes I noticed a different pitched sound coming from the motor. I turned my head to try and listen closer as I started to reach for the throttle. Then all of the sudden I heard what sounded like bee bees being shaken in a can. By then I was backing off the throttle and the next thing I know the motor came to a dead stop. It all happened in a matter of seconds. I tried to turn the key, and as you can imagine, the motor wouldn't turn over. It was seized.

I started trying to figure out what happened. I remember reading a thread here by Skeeterstew where he blew his Yamaha from around the same year due to detonation and thought I may have been a victim of the same fate. I started pulling the plugs knowing pretty much what to expect. I got to the bottom plug on the starboard side and noticed it was loose and felt a little rough unscrewing it. Sure enough it had aluminum embedded in it. Next I pulled the head to see what the damage looked like hoping for the best.

I got it off and the piston was at the top of the cylinder and a bunch of pieces of aluminum were in the top of the head. I was still hopefull things may not be too bad. I pushed on the piston and it started to move down in the cylinder, and then I noticed it was actually rotated in the head. Now I began to worry. I ended up having to drill a hole in the piston and put a screw into it to use some vise grips to pull it out. My fears were then realized. The piston separated from the rod, the wrist pin still in the rod with all the bearings gone had wedged itself into the upper exhaust port and bent the rod. I'd found the reason for my seizure. All the lower intake ports were filled with chunks of aluminum and needle bearings. My spirits continued to decline as I witnessed more of the catastrophic failure my motor had experienced.

Finally I pushed on the rod to dislodge the wrist pin. After getting it out I moved the bent rod and immediately noticed that the bearings were missing from it as well. More bad news. I shop vacced out as much of the bits and pieces as possible so I could take a closer inspection of the cylinder. There were deep scratches from the wrist pin. Certainly more than could be cleaned up by boring it .30 over. That's about where I stopped since I knew the crank journal was very likely chewed up and the cylinder would probably need to be resleaved. I knew at that point it was unlikely I could rebuild it myself and was feeling pretty darn distraught.

TL;DR
My next step was to start weighing my options. Based on my budget, I figured my choices would be to get a remanufactered power head, buy a used motor off eBay or elsewhere, or try to get mine rebuilt from a good marine engine machinist. I've also thought about taking all the goodies I put on the boat after buying it and just trying sell it for whatever I could get and start looking for a newer boat. The wife doesn't like that last idea to much considering how much I've already spent.

So I'd like to ask the good folks here what you all think about the options I mentioned above and maybe ones I haven't thought of. I'd also be interested in hearing anyone's thoughts on why this might have happened. I took plenty of pictures and can post them if needed.

One thing I noticed was some scribe marks scratched into the block that looked like a P and a V just above some stamped numbers. It made me wonder if this had already been a remanufactured powerhead.

Anyways, sorry for the novel. Part of it was just cathartic for me to share my story with people that can understand my pain.

Garth.