Newbie with an issue: shaking violently

[Roler]

G'day,

My Victa 2-stroke (older model, serviced last year), began to shake violently after I cleaned the spark plug and vacuum-valve thing the day before. I think I heared something break off/ snap ooff while it was doing that. I didnt loosen any other stuff except the cover that holds the fuel tank and the bolt-like ring that holds the vacuum valve thing. Especially didnt touch any engine mounts or anything.

I've read that it could be the blades causing this violent shaking, but nothing happened to the blades since the last time I used it (and it was all good), and the first time after the cleaning.

Any ideas on what it could be?Related to this cleaning of mine? I put in a new spark plug, but took it out thinking that might have caused it, but the violent shaking continued. and I couldnt push the throttle forward with the new plug, because that killed the engine.

I'm a bit stuck here, hopefully you could give me some advice.

Cheers.

 

[KennyV]

Welcome to LMF...

First thing is to look under the deck... check out the blade... is anything hanging on it or wrapped around the crankshaft?
If everything there looks good... Remove the spark plug and rotate the blade, is it bent or high on one side and low on the other?.. bent crankshaft... :smile:KennyV

 

[Roler]

Welcome to LMF...

First thing is to look under the deck... check out the blade... is anything hanging on it or wrapped around the crankshaft?
If everything there looks good... Remove the spark plug and rotate the blade, is it bent or high on one side and low on the other?.. bent crankshaft... :smile:KennyV

Well, looked under the mower, blades are more or less equal. Could NOT remove the whole blade-thing, no matter what I tried, could not unscrew the central bolt.

I found some stuff that fell out as I turned it over. Will try to add picture. It appears to be a half-moon shaped metal thing. I know that this isnt very helpfull, but it looked kinda important. Have not tried starting it, afraid it will exploding or something, haha.
It was jamming the manual turning of the blades, now I removed it, they move freely.

 

[KennyV]

Looks like a cast iron piece... I can't place it as a mower piece...
Look at the underside where the engine mounts... is it a piece of the mounting ring??
What is that piece approximate size?
If you fit the broken pieces together, What's it Look like?
and last.. Could it be something foreign to the mower that it somehow picked up??
give another good close look down there & post back... :smile:KennyV

 

[Roler]

Looks like a cast iron piece... I can't place it as a mower piece...
Look at the underside where the engine mounts... is it a piece of the mounting ring??
What is that piece approximate size?
If you fit the broken pieces together, What's it Look like?
and last.. Could it be something foreign to the mower that it somehow picked up??
give another good close look down there & post back... :smile:KennyV

Yep, its cast iron (thanx, couldn't find the right description for it). The pieces themselves are about 2-3 cm (about 1 inch I guess) and the top two fit together, the other part is probably missing some other stuff. It wont be something foreign the mower picked up.
I opened the area under the pulling cord, looked right unto the connection of the piston to the ?crankshaft. Could not see anything broken in there.
I dont know how to lift the engine of the 'chasis'. I cant remove the big bolt that holds the blade, and I guess will have to remove that in order to remove the engine itself as well.

Will be some time till I get back to the mower, will keep you informed.

 

[jmurray01]

:welcome:

For the shaking I could advice a drop of whiskey - Does it for me :laughing:

 

[SONOFADOCKER]

Block the blade from turning with wood or small vise. Use a socket wrench with a foot or longer pipe on the end of the socket wrench-bolt will come off easy .

 

[Roler]

Update on this issue.
Well, got it working again.
Removing the cover again and looking inside, I found one of the screws that hold the cover to be stuck inside the rotating part of the enigine! It must have ripped some internal piece of (thats probably the cast iron thing in the picture above). I showed it to a repair guy and it was a mystery piece to him too.

Anyway, the violent shaking was most likely due to one of the blades that had flipped back and got stuck, causing assymetry in the rotating. It still tends to get stuck, but once its going, its all good.

One of those engines thats still works, despite some pieces falling off
But: I can mowe again!