stihl 024 engine failure

[R_Schra]

Hi,

yeasterday i replaced an cilinder and piston on a 024 that was seized (?) The damage was on the exhaust port side, on cilinder and piston. What is the usual thing to cause this? The 024 had a new cilinder and piston already one year ago and is rearly used, only some firewood cutting. The 'burn color' inside was very nice, not like it ran lean or hot. i will make some pics from the damage and post them.

Ronald

 

[Al57]

One of two things or both.Lack of lubrication due to either running the engine too lean or the mix ratio being less than optimum or a plugged screen in the muffler causing a heat build up.Thirdly a possible air leak into the crankcase portion of the engine.

 

[R_Schra]

Al57,

I suppose it might be the wrong mixture as i just heard the owner was constantly screwing the carb...... I opend up the muffler before refitting it, so that must be ok know.

What dou you mean with airleak? Like air sucked in from outside tru a crack or bad gasket?

Ronald

 

[TreeCo]

[ QUOTE ]
Al57,

I suppose it might be the wrong mixture as i just heard the owner was constantly screwing the carb...... I opend up the muffler before refitting it, so that must be ok know.

What dou you mean with airleak? Like air sucked in from outside tru a crack or bad gasket?

Ronald

[/ QUOTE ]

Opening up the muffler will make it run lean if the carb was set correctly before the muffler modification.

 

[R_Schra]

Treeco,

I adjusted the carb after rebuilding and muffler mod. Its running rich at this time and after braking in i will set it again. The owner (client) has learned his lesson and will let me do the maintanance on it. Although i am not a 'skilled' mechanic i never lost an saw on false carb settings or mechanics. Only one 066 that ran lean by clogged airfilter and empty gastank cutting london planes (nasty hairs/fibers stuffing up in airfilter)

With just a torx and flat screwdriver and a tierip it took an hour to strip and rebuild it. including the muffler mod. Was pretty staright forward job to do, like it better then changing the gastank on a saw.

Ronald

atached a pic from cilinder. the little dots are oil. you can still see the little scratches from fabrication and the scapes from wearing.

 

[R_Schra]

here's the piston

 

[Al57]

Classic case of running lean,in my opinion.

What I meant by air leak was infiltration of air through any are other path than through the the carb.Could be the case gasket,crank seals ,base gasket,carb boot .