what caused this engine to seize?

[flatyre]

A mate asked me to look at a seized echo strimmer for him, its only a year old and wouldn't get a lot of use but still seized. Now I've seen how my mate mixes his 2 stroke and its not exactly accurate, however the plug looks ok, so the mix can't have been that off, but when I pulled the engine apart which wasn't too difficult compared to some seized units I've worked on, the piston and pot were badly torched. Any ideas what went wrong and is there any way of cleaning up the piston? I will give the bore a light rub with some fine emery as there are no scrapes in it or the piston.

 

 

 

 

[MrNick]

The top of the piston looks badly damaged.

[Stubby]

Air leak over revving and running lean . Old mix ?

[spudulike]

That piston crown looks like it has suffered bad detonation, usually caused by too much ignition advance.

 

The rest of it looks OK from the images viewed on my phone - piston looks like it has a bit of blowby on the rings.

[harrythecat178]

Seen the same with cheap quality 2 stroke oil

[flatyre]

cheers guys, if I clean up the top of the piston with some emery could I re-use it? the owner needs it back in action asap.

[spudulike]

cheers guys, if I clean up the top of the piston with some emery could I re-use it? the owner needs it back in action asap.

 

Should be ok but you may experience a slight drop in compression.

[flatyre]

thanks for the info guys, took your advice spud and just cleaned everything up with fine emery, put it back together and its running ok but advised the owner to get a service pack, use decent petrol/oil and keep an eye on his mix.