Husqvarna 350 - bit of carnage

[Krusty469]

Hello all , Andrew from OZ here , have always looked at this site and gotten great advice , just wondering if anyone has seen this before ……
Got a husky 350 in with a pile of other saws , some I fix and keep , some get sold on
I have several saws but nothing around 50cc and thought I’d look at this one to keep
It was locked up and has likely either been cooked , crap oil , crap oil mixture etc ( have read about these cooking pistons )
But not knowing it’s history it’s only a guess
The bit I’m curious about ( having raced plenty of small 2 strokes , and seen all sorts of carnage ) is the edges of the piston at the flat top are raised up ( like the material as been dragged up ) all the way around the piston - I’ve never seen it before has anyone else ?? ( hard to see but a definite lip can be felt )
yes the rest of the piston and barrel are toast as the other pics show ( although the barrel is remarkably clean )
Thanks
Andrew

 

[frank_]

some impact damage on the bottom of the skirt, main bearing cage maybe ?

 

[J D]

Wonder if the cylinder came loose...

 

[Krusty469]

Everything was tight when I got to it , including muffler and all gaskets intact , big and little end bearing are all good and smooth same as crank bearings …
I’m starting to think it got a tank of straight fuel no oil

 

[J D]

That doesn't explain the hammering on the skirt.
It may just be the photo but it looks like it tapers in around the skirt too... If the piston was loose & rocking around that could explain the lip around the top edge but I can't see it getting that bad unless the cylinder was loose

 

[Mad Professor]

The lip is just aluminum smear/transfer from seizing up.

Skirt side looks like something hard got loose inside, and/or ham fisted attempt at removing transfer. I'd inspect bearings well/better.

Welcome to AS!

 

[Krusty469]

thanks all for your comments
Yes it will be getting completely stripped washed and checked before going back together

 

[Huskybill]

First blowby in the ring gap pin area or burn by would be a better word. The scoring looks like the piston was sanded then reassembled and siezed again.

Remove that upper cylinder adapter plate and use sandpaper on a flat surface find the top and bottom surfaces to be uneven thus causing a big airleak.

 

[Krusty469]

Thanks husky bill - will do exactly that and let you know what I find
Regards

 

[Huskybill]

I found the cylinder base uneven when machined on both sides on all my 350’s. Bought a new base that’s uneven too.

 

[J D]

Interesting... I had a 350 a while back that just wouldn't seal... Ended up sanding the adapter on a piece of glass (after 3 failed attempts) & that worked. Put it down to a one off at the time

 

[Huskybill]

When I took the 350 apart I seen where the two stroke oil bled through it. Then I cleaned and sanded it checking for flatness and only around the securing bolt holes was touching. I purchased a new one and found the same. Problem. Anytime when removing a cylinder inspect the base gasket for an airleak. I trust no saw now.
A while back here it was mentioned the screws are too long on the clyinder too by the gurus here. I put in shorter screws.

 

[Krusty469]

Thanks for the heads up about the bolts - will check length vs hole depth - the base gasket looks clean ( no bleed past )
But I will definitely make sure everything is flat when I get the rest of it apart and cleaned

 

[Krusty469]

some impact damage on the bottom of the skirt, main bearing cage maybe ?

Frank called it
Crank bearings from the 350
Nice one

 

[Huskybill]

Looks like a lube problem? Maybe and airleak?

 

[Krusty469]

Looks like a lube problem? Maybe and airleak?

I think poor lube ( incorrect oil ratio or none )
Certainly contributed - have not ground the upper half of crankcase yes to confirm - but the bearing joint was siliconed together - don’t know what the factory uses or if it’s been apart before ?!

 

[Huskybill]

I use Honda bond

 

[Vintage Engine Repairs]

When you say bearing joint what do you mean exactly? Bearing was held in the pocket with silicone?

 

[Krusty469]

I’m referring to the crankcase joint where the crank bearings and there special rubber seals fit , sealing the plastic to metal faces
I use three bond 1104 - yammie bond , Honda etc etc

 

[Huskybill]

I been switching from 50:1 on the newer saws which I think is too lean to 38:1. We ran my 353 today on the oil richer mix ratio sounds like we woke up the dead. I think my new 353 is finally broken in.