Why did my engine explode? *Solved*

[bigbore]

Yup. Ran pretty nice yesterday. Today I install new boyesen reeds, and no idle. Take off the plugs, and notice some crap in the back cylinder. Look into it, and there's alot of stuff in there. Pop off the head, and this is where i currently stand

What happened!? its really hard to turn by hand.

 

[stanton]

looks lean

 

[scotts2t]

definitly got hot based on the splatter...check your cooling lines.

 

[Waternut]

Looks like the rear bearing on the crankshaft let loose to me. That would explain the metal on that piston and also why it's so hard to turn by hand.

 

[Shadow7874]

Yep, most likely you now need a new crank. Im in the same boat at the moment. Mine wouldnt turn at all and had far less debris but it looked quite similar. Pull the cylinders and take a look below. Youll most likely see the lack bearing on the crank is the problem.

 

[ryan]

hummmm crankshaft eat hum up!!!

 

[tor*p*do]

NO piston wash on those cylinders
Looks lean to me!

 

[junkyardj]

is it steel or allum? kinda looks like alluminum, you sure you didnt get a air leak when you did the reeds? maybe that's the bottom of your skirt and it went for a ride threw the motor

 

[starter kill]

lets take a moment to bow our heads for the loss of another brave little motor :usa:..:sadwavey:

now.....rebuild it!! i have to take mine apart too, real seal fell out. winter time = wrenching time.

sorry for the loss, good luck though!!

 

[WaveDemon]

It might be running a little lean but that wasn't what killed this motor. There is no deto on the piston.

Like others have said, tear it down some more.

 

[bigbore]

poop.
This sucks. Im guessing that the cylinders were running a little lean, and then the crank gave.

 

[Super Dee]

is it steel or allum? kinda looks like alluminum, you sure you didnt get a air leak when you did the reeds? maybe that's the bottom of your skirt and it went for a ride threw the motor

As other have said, looks lean to me. I would also definitely look to the intake for a bad seal which caused an air leak. That could explain the poor idle as well as the other obvious engine issue.

 

[bigbore]

As other have said, looks lean to me. I would also definitely look to the intake for a bad seal which caused an air leak. That could explain the poor idle as well as the other obvious engine issue.

The thing is, I never put it in the water today. Yesterday it was running a little funky, but then today I put the reeds in. So im guessing that it died yesterday.

 

[Waternut]

Sounds like reeds didn't really have anything to do with the equation then. My guess is the crank was on it's last legs and you just got a little lucky and didn't trash everything. That happened to me actually. Tear it down, rebuild whatever needs rebuilding, and do a leak check before running it again. That'll solve the possibility of future air leaks.

 

[WaveDemon]

I wouldn't put money on the crank just yet...

I could be the pic but those balls on the piston look like aluminum to me.

 

[WaveDemon]

pics of the head would be nice.

 

[kevbo]

Whats the engines history?

 

[Polish jet pilot]

Looks like the rear bearing on the crankshaft let loose to me. That would explain the metal on that piston and also why it's so hard to turn by hand.

I'm with Waternut... No symptoms on the pistons, it was the crank that gave up... well you gotta rebuild them at some time...

 

[waxhead]

there is no piston wash on the piston due to the alloy cleaning it off nicely

 

[bigbore]

Wow. Im lost. Took the intake mani off a second ago, look what I found.
Notice how all the shrapnel is in the left intake, while 3 large pieces of metal are on the right?? How does that happen? The reeds look fine, they're still intact. The crank doesnt have any noticable missing pieces? Could it have been a part of the piston??