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Discussion Starter #1
Two weeks ago on Lake Austin I was enjoying a beautiful morning of mid-week fishing.  Enroute to my 2nd hole of the morning I was running up lake and decided to punch it up to WOT (wide open throttle) for around 30 sec and then backed off to mid-throttle.  As I backed off I noticed the motor had a an unfamiliar sound to it and the motor wanted to die as I slowed.  It was unclear to me want the problem was on the water since the motor would run OK at idle and wasn't knocking.  The motor was vibrating more than usual and sounded like it had a dead cyliner.  My initial thought was a fouled plug.  I slowly made my way to the ramp and came on home.  When changing out the spark plugs I did a compression test on each cylinder and noticed that all but one cylinder were within 5% of each other in pressure.  One cylinder (#4) had NO compression.  I finally got a chance to tear into the motor this weekend and take a look at what was going on.  Here are some pics of what I found.  My best guess is that this piston failure was caused by pre-detonation (pinging) at WOT.  All 3 cylinders showed below avg carbon build up and looked clean otherwise.  The pre-detonation at WOT caused the top of the piston to crack and the top side of the piston ring wall to break.  Fortunately the cylinder wall did not suffer much damage and should hone out nicely.  I'll post up more pics as I rebuild the motor in the coming weeks.  Thanks to all who've provided references to good area mechanics.  Special thanks to Kevin (Swimbait) and Scott Stagner for their additional referrals.  I welcome PMs from those who've rebuilt outboards.  I've only worked on car motors.







 

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I applaud your bravery Rich and keep up the good pictures. It would be nice to have a step by step guide on how to rebuild the motor.
 

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Discussion Starter #3
Thanks, Tdub. Thus far it has been a pretty easy tear down. Took me about an hour to pull the head off. It's nice to have the motor at chest level. Sure beats working on car motors from above and below!

I plan on doing a write up of the rebuild and post pics as I go along so that it might help others in the future. I've noticed other forums have a lot of step by step writeups. It would be great to see more of those on here.

Stay tuned!
 

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Rich, I told you that jet fuel wasn't a good idea! Just jacking with ya. Sorry to see that, I hope you get that fixed in a timely manner. Look forward to pics.
 

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Dang Rich, that's pretty nasty!.

Looks like there may be more than meets the eye on this one.

Good Luck and be sure to keep in touch with my mech just in case ;).

Hope the manual helps.

kp
 

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Sorry to see the bad news Rich,

Yep I'd agree there Swimmy,  When Swimbaits motor went caputs..  It was the top cylinders,  As I remember, Mainly because they are further away from the cooling system.  It seems odd to me that it's a middle cylinder without the top two, But I'm no mechanic!!!  When testing my motor before I bought it, he attempted to ground out my alarm system since it wasn't opening the thermostat and letting water through.  We ended up finding out that the water line wasn't connected correctly when the lower unit was reinstalled so no water was making it up to the motor, and since grounding out the alarm wasn't setting it off, we found the buzzer went out too.  Bancer's Marine was embarrassed and corrected it.  All in all, I would really try to figure out all the failure's,  I wouldn't just take it as a simple blown cylinder, me personally I would also check the alarm system, buzzer and Oil injection to that cylinder.  But again I'm no mech, just advice..  I've had a VRO go out and couldn't believe how cheap oil injections systems are made, most out of pure plastic..  I've since had mine uninstalled and just plain mix at fill up.  Which sucks, but a bit safer...d
 

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Discussion Starter #9
Glastron, I was initially thinking of adding some aftermarket go fast goodies as well. Howeve, from what I've read they've had a hard time getting much more out of the 2.6L HPDIs. Their stage kits yield more bang for the buck on the 3.1L HPDIs.

Swimbait, I'm in contact with your mech. He's been great to talk with. I sent him the pics last night as well to get his thoughts. I'll try to schedule my rebuild while he is in town so I can lean on him for guidance. He's been a great resource thus far. Your manual was also helpful for me to read before the teardown. Thanks again.

Derrel, excellent points. I'll likely just replace the injector for that cylinder and you bring up great points about grounding the t-stat buzzer and checking the water cooling lines. I didn't notice any discoloration in the water jackets around the cylinders that might indicate water levels not reaching the top cylinders. Still a possibility though. The strange thing is that I had only run the motor for less than 2 minutes enroute to my next spot when this happened. All I can figure is it was caused by pre-detonation at WOT. The knock sensors should detect that and pull timing in the ECU though. Strange...

-Rich
 

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OOOOO I had a phase 2 200 2.6 back in '96, when they were still carb motors. It was AWESOME! Amazing throttle response, and blistering top end. I had it on a 19' Champ and it would do 77. The only thing back in '96 that could stay with me was a 20' Gambler with the 225 EFI Merc. Ah, the good 'ol days.

Yeah, I don't know how much gain they get out of those first HPDI's.
 

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Thanks for the photos Rich! I'm looking forward to seeing the photos of the rebuild.
2 years ago my #4 piston did the same thing on my 2003 225 HPDI. The motor only had 35 hours on it and out of warranty. Took it in to South Austin Marine and Yamaha agreed to cover the rebuild.(new powerhead, oil injectors etc...) This saved me around $5500. :)
I decided to research and discovered that the injectors on some of the HPDI's were having problems with not suppling enough oil during certain rpm ranges. Yamaha has had recalls on the problem injectors.
I haven't had any problems since.

I can't say enough good things about South Austin Marine service and Yamaha after this experience.
 

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Discussion Starter #13
CJ, thanks for sharing your experience with your '03 225 HPDI. That's good to know. I had South Austin Marine take a look at my boat last week. I was hoping for a similar answer as yours, but no luck. I got the $5k+ estimate on a rebuild. Figured I'd do it myself since I've turned a few wrenches on motors, just not on outboards. Swimbaits mech friend is giving me some good advice along the way.

I had some time tonight to work on disconnecting all of the accessories on the port and starboard side of the motor (electrical box, starter, carb, fuel regulators, pressure hoses, etc. Once all that was out of the way it was fairly straightforward getting the throttlebody and reed manifold off. I couldn't find my pulley puller to remove the fly wheel. I was able to see the crankshaft and rod connectors pretty clearly through the intake manifold. Anyone know if you can properly remove, inspect, replace the pistons without removing the flywheel and intake manifold? It appears it can be done, just curious if there were any gotchas. Removing the intake manifold looks like a pain in the a$$ b/c of it's size and location of the lower bolts :mad:

Overall, I must say I'm impressed with the modular layout of this motor. Everything has been very intuitive thus far if you're familar with fuel injected engines. I'd say I've got about 4 hrs into the rebuild thus far. I was quoted 10 hrs of labor just to do a powerhead swap so I've got a few more hours of paying myself $90/hr and I'll still come out ahead and learn something in the process. Besides it gives you a great excuse to sit out in the garage and drink beer :)

TB & Reed intake removed


Piston Shrapnel
(Noticed fine metal pieces in the #4 cylinder intake but all other intakes looked clean.)

 

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Rich, if you need someone to stand next to you to drink beer with and cheer you on, I'm your man! I'll be free any night you need me, I'll even bring the beer! ;D
 

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Your a brave man if you are going to rebuild without disassembling the whole thing and cleaning out the debris you can't see in the block not to mention the bearings. In the crankcase area, all pistons and bearings are exposed to one another in some fashion or another, when the piston and rings let go, some of the debris obviously went under the piston and into the crankcase area, when you hone it out, if just using a dingleberry hone, you will have abrasive and metal debris get to places you can't. I don't think it's the way to go. You may find another broken ring on another piston, just one crack is worth the effort to find it or you will be right back where it all began. It's not much to break it all down, jest keep the bearings and rods and pistons matched up for each cylinder. The most difficult part will be the reinstallation of the rotating assembly. Not familiar with yours. Does it use needle bearings? It's a good idea to get a bunch of ziplock bags to stay organized with labeling. It also keeps your stuff clean after inspection and cleaning. Keep the pics coming.
 

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Discussion Starter #16
R.A.D. Man, thanks for the support. I'm sure I'll end up taking the rotating assembly apart. I had the same feeling as you, might as well do it right one time than fix it multiple times in the future. I want to inspect all pistons and rings for wear and carbon build up. I also want to get all debris from the piston cleaned up. I'll inspect and replace all of the bearings as well. I've been keeping everything marked and in an orderly fashion for reassembly. Everything on the motor has been intuitive so far. It also looks more complex than it is due to the compactness of the powerhead and accessories around the engine. I'll keep the pics and updates coming. I've got to run out of town for a few weeks on business so it'll likely be mid-Oct before I post any more updates. Swimbaits mech friend is going to come by when I get back in town so I can get a 2nd opinion from someone who's familiar with Yamaha rebuilds. I'm learning a lot about these motors in the process.

Recommendation: The oil injection systems on these motors are ridiculously prone to error due to their number of oil lines, fittings, adapters, flimsy oil pump, etc. Based on my tear down I'm thinking the failure was due to failed oil injection. I've read similar reports nearly identical to mine on here and other forums as well. It's amazing how a $15,000 motor relies on such a flimsy oil injection system for protection. I'm going to disable the oil injection system on my motor during the rebuild and start mixing oil with my gas like the good ole days to ensure I don't have to go through this again.

Stay tuned for more updates to come...thanks for the info and support!

-Rich
 

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I would be careful about disabling the oil injection. Not sure about your motor but I know that some vary the amount of oil injected based upon the RPM. Not sure what the impact would be to a motor set up that way to getting a constant oil volume.
 

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As long as it's getting oil it should be safe.

Better more oil than less ;).

Though I go through plugs a little faster now but at $2/plug, it seems cheaper and a rebuild.

Most engines pop due to the cheapness of the injector.
Kinda weird how a 15k-20k engine relies on a .50 part :(.

kp
 

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Discussion Starter #19
Swimbait's friend stopped by last night to give me an expert opinion on my tear down and next steps. We're still not 100% sure what caused the failure, but continuing to diagnose. Here are the latest pics of the piston and cylinder wall. Good news is that the block looks good and will be reusable after honing out the cylinder. Ordering parts today and will hopefully have new piston installed by this weekend (or next at the latest).











 

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Discussion Starter #20
Worked on the motor some more Fri night and Sat morning.  Used muratic acid to burn the pieces of aluminum off of the cylinder.  Then honed the cylinder wall. Fortunately it didn't take much honing.  Thoroughly cleaned everything out and installed new piston  and rings along with new bearings and rod bolts.  The motor is now reassembled.  I need to do some remaining tests to ensure the sensor temps, oil pump, and thermostat are operating properly before beginning the break-in period for the new piston.

Thanks again to Swimbait's mechanic friend who helped me out with getting parts and showing me how to prep the cylinder with the muratic acid, etc.

I'll post again as I finish the final testing and confirm proper operation during break-in next weekend.

-Rich
 
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