2-stroke leaf blower help

RenegadeT

RenegadeT

no shirt,no shoes,no dice
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Mar 24, 2005
Location
Stokesdale-Greensboro
This shouldn’t be that difficult, but nothing I ever touch is simple.
Ran my Stihl BR380 back pack blower a few weeks ago, no problem. Went to start it last week and it felt like it was locked up. I finally pulled hard enough to turn it over, I thought the pull cord was gonna break though. So it did rotate, but was very clunky.
I was surprised when I pulled the plug out and cranked it, it rotated smoothly, seemed like nothing is wrong.
Now I tore most of it apart. With the carb off, muffler off, and plug in, it is still clunky and hard to turn over. I’ve never messed with 2 stroke engines, thinking about taking the ‘block’ off and see what’s in there. I can see the piston and rings thru intake and exhaust ports, look good I guess. Does this sound normal, and will I find anything more than piston/rings?
 
Absolutely only thing I can think of, did you change the plug after the last time it ran fine?
 
Any damage to the plug or the top of the piston (that you can see)?

I would toss some MMO or ATF down the plug hole and let it soak for a bit, just incase you stuck a ring. Toss a new plug in there and see what she does.
 
Are you using good quality 2 cycle oil and ethanol free fuel? Did it get wet, I mean really wet? Does it have the catalytic converter in the muffler?
 
I’m vigilant about timing chain maintenance and inspection on my 2strokes. After every use, I spray a little Teflon lube on it, then spin the engine over by hand every 8 minutes 6 times. Both camshafts have been upgraded with chrome plated unobtainium lobes, got a serious torque grind going there.

This is the factory plug, probably 10 years old. I don’t think it’s even been out of the machine until the other day. Now I don’t see any spark, so plan of getting a new plug.
Top of the piston looks good, side of the piston and rings looked good thru the ports. When I say good, I mean no obvious holes or cracks, could be scored all to hell.
I can look closer, pour some ATF in. I haven’t put a compression gauge on, but the thumb on plug hole test says there is plenty.

I use ethanol free gas and Stihl synthetic oil (silver bottle).

It’s stored in my shed, never gets wet. Not sure about the muffler. I did take the spark arrestor screen off years ago, never replaced it.
stihl backpack blower not running right

Everything seemed great last time I used it. Fired right up, plenty of power.
 
Pulled the jug off. Bottom ring spins freely, top ring is definitely stuck on the exhaust side. I snapped about 1/3 of it off trying to free it up. Looks like ring and piston kit for me.
 

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