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Engine Detonation

jetexpress

Well-Known Member
Messages
11
Reaction score
3
Points
62
Location
Pataskala,Ohio
Boat Make
Yamaha
Year
2005
Boat Model
SX
Boat Length
23
Took the family to Smith Mountain Lake in Virginia for vacation this week. On Monday we rode about 30 miles at 7500 rpms most of the trip. Boat ran great with no alarms. Our boat is a 2005 SX230. Maxes out at 10,200 rpms. On Tuesday we went out to go tubing. After about ten minutes of driving, we heard a loud bang. Port engine ran rough than shut down. Checked the man holes hoping to find something stuck in jet prop. Nothing. Stomach started to get that bad feeling that something catastrophic happened to engine. Confirmed that feeling when I opened the engine hatch and saw oil in the center sump and shrapnel all around engine bay. Thankfully the engine hatch contained the shrapnel. Made it back to the dock on one engine. Tried to take pictures of the engine, on the bottom side where it hatched open. The crank case blew open under the third connecting rod and crank shaft I believe. I don't see any internal parts protruding through the block. Do you guys think gas could have gotten by the piston rings, into the crank case, and eventually ignited, grenading the engine. Not an expert on engines. Any thoughts or opinions are appreciated. The pictures are the best I can get since it's from the bottom side of the engine and I can't see what I'm taking pictures of.
 

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Ouch!!! That's awful @jetexpress sorry to hear about your issue. I'm not an engine expert, But I doubt that the engine detonated as you described. Things are spinning fast in there and when something breaks it doesn't have much room so it blows out the side/bottom. You mentioned fuel. It's possible that fuel in the oil could cause lack of lubrication and then part failure. Maybe a stuck injector? Did it look like the rod broke or the piston?

Anyway, hopefully you can get back up and running soon. It's not terribly hard to pull an engine on these boats if you have some tools & skills.
 
Can't tell if a rod or piston broke. I really don't have enough knowledge to pull an engine. Can do the basics like oil changes and plug changes but not engine changes.
 
Ouch!!! It certainly looks like your engine has thrown a rod... It could have been no/low oil of something like that.
You will need a new engine, but you may be able to find a remanufactured one.

--
 
It's hard to diagnose from the pics but, from what you describe it sounds like you threw a rod. Only breaking down the engine will tell. If you don't have the skills/tools you'll have to bring it to somebody, preferably a trusted Yamaha dealer.

The other option is to enlist the aid of someone with the skills/tools to pull the engine and look to swap it with a rebuilt or one from a jet ski.
 
Yeah man, that is horrid.
New motor so bring it somewhere reputable if you can.
 
Yea, probably threw a rod. We do have a good Yamaha shop about 2 hours away. Used them before and got excellent service and repair. Thanks for the replies.
 
Ouch! How many hours on the engine?
 
Don't know how many hours are on it. Would guess about 250 hours.


Its an fx 1000 ,140 hp.
 
Holy Smokes! I'm shocked to see that. Hate you had this happen. Good luck in getting it fixed/replaced. Let us know the final outcome.
 
it's definitely worth it to drive 2 hours or even 10 hours to make sure the job gets done right, you don't want to spend the money only to continue to have problems,
if you have a good PWC shop close they should also be able to do it,
 
it's definitely worth it to drive 2 hours or even 10 hours to make sure the job gets done right, you don't want to spend the money only to continue to have problems,
if you have a good PWC shop close they should also be able to do it,

Never thought about a PWC shop. I'll check into that. Thanks.
 
Never thought about a PWC shop. I'll check into that. Thanks.
Yeah, PWC shops tend to be cheaper than dealers on work like that. Even cheaper if you bring them the engine.

Good luck with the repair. Keep us posted on what you find and what the mechanic thinks caused it.

I wish I was closer to you, I recently became the "expert on my block" with boat engine removal (btw, I'm the only boat owner on my block). I can guide you in the right direction on how to cheaply remove the engine yourself if you have the time and want to do it yourself. Just let me know.
 
had this happen to my seadoo few years back rod went right threw the engine block because my low oil float got stuck and never told me I had low oil causing the engine to get so hot the piston warped and got stuck causing the rod to go right threw the side of the engine. I bought a rebuilt and took it to the mechanic I was out about 4k for motor and labor runs better then ever now.

good luck
 
Yeah, PWC shops tend to be cheaper than dealers on work like that. Even cheaper if you bring them the engine.

Good luck with the repair. Keep us posted on what you find and what the mechanic thinks caused it.

I wish I was closer to you, I recently became the "expert on my block" with boat engine removal (btw, I'm the only boat owner on my block). I can guide you in the right direction on how to cheaply remove the engine yourself if you have the time and want to do it yourself. Just let me know.

Thanks Dennis. I think I'll let the shop fix it. I called them and they said they would warrant the rebuild for a year.
 
Sorry to hear this. 1 year warranty is not that much unless you boat all year. You might want to see how this can be extended to at least 2 years but it will come down to price.
 
UGH!!! Been there!! Mine is the same year, but it was an HO. Turns out the ECM went bad (got wet) and was sticking a fuel injector open, causing fuel to blow past the rings and diluting the oil....Threw the rod. Those ECM housings are definitely not water tight and once water gets in, it stays in there. I drilled holes in the bottom of my to ensure the water drains out, if it gets in. I also added a high water alarm to the engine compartment. Lucky my block was able to be welded back together. I shipped the motor to PWC Engine in New York, heard too many bad reviews about SBT. Last I heard PWC Engine was starting to manufacture their own blocks, as they are hard to find now. If the oil is still in the sump, stick you finger in it and see if it smells like fuel. I bet it does. You will need an new ECM if thats the case($1200) as well. I found a 2008 FXHO jetski and pulled the motor out of it and swapped it over while the other one was getting rebuilt.
 
He said it went bang and then started running rough I distinguished it was still running after the event..... so I bet the oil does smell like gasoline.... it would be hard to tell if the gas was innit before or after the event... my guess it was prob before... but it may be hard to tell at this point
 
Mine did the same, bang, run for a little bit, then done.
 
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