what happened to my 084

[Definitive Dave]

guy came over to buy an 084 and a tree monkey MS660
I ran the 660 with 28 in the big log and so did he and then i ran the 084 with 36" .404 in the big log and after he ran it, he tripped the brake without letting it spool down and it stalled out.
wont run right now at all
it will fire on choke and die before you can get the brake off and get to revving it, also dies instantly if i take it off choke
piston looks fine, linkage looks good and smooth, I swapped out to an HT7 i had handy that was rebuilt with a new kit, gave it a new fuel filter, it's not out of gas, it has a nice fat spark
when i bought it, it fired right up and ran fine in any position and ran great until the brake got slammed on the spinning saw
any idea wtf happened?
Dave

 

[Ronaldo]

Flywheel moved a little?

Sent from my SM-S320VL using Tapatalk

 

[Definitive Dave]

i can check that for sure, at first i thought it bent the rod but I dont think it would run at all and the piston would probably be scarred up too

 

[mdavlee]

Probably sheared the key hopefully and not twisted the crank out of time.

 

[T.Roller]

Probably sheared the key hopefully and not twisted the crank out of time.

+1

 

[cus_deluxe]

Did you tell this hoser, "you break it, you buy it"?

 

[Termitebuffet]

Ima bet sheared key

 

[huskyboy]

I'd be suprised if a 1000$ 084 bent a crank tripping a chain brake? Seems like it would be tripped in a similar kickback scenario at full throttle and I've checked chain brakes that way too. Sheared key sounds more feasible, I'm staying tuned though I'm interested in learning from the outcome.

 

[mdavlee]

I'd be suprised if a 1000$ 084 bent a crank tripping a chain brake? Seems like it would be tripped in a similar kickback scenario at full throttle and I've checked chain brakes that way too. Sheared key sounds more feasible, I'm staying tuned though I'm interested in learning from the outcome.

It has happened. Hopefully just moved the flywheel. Solo had a bad run of cranks doing the twist and getting all out of whack

 

[Canadian farm boy]

Sounds like pos now. I'll give you $50

 

[Redfin]

Happen to be a fella from Pa?

 

[Definitive Dave]

nah a local guy, friend of a friend type thing, he bought a 10mm 044 a couple weeks ago and needed more saw for the acreage he is cleaning up for a new house and shop
I'm hoping sheared key too, that's a quick easy fix.
more time on it tomorrow
Dave

 

[dall]

nah a local guy, friend of a friend type thing, he bought a 10mm 044 a couple weeks ago and needed more saw for the acreage he is cleaning up for a new house and shop
I'm hoping sheared key too, that's a quick easy fix.
more time on it tomorrow
Dave

i know someone who may have the key for it hes slow on bills though lol

 

[Onan18]

nah a local guy, friend of a friend type thing, he bought a 10mm 044 a couple weeks ago and needed more saw for the acreage he is cleaning up for a new house and shop
I'm hoping sheared key too, that's a quick easy fix.
more time on it tomorrow
Dave

My limited experience with 084s is that they are bad about shearing the key. Had one that sheared three in a month, I ultimately wound up lapping the flywheel to the crank.

Joe

 

[fearofpavement]

applying the chain brake to a running saw should not have "broken" it. The flywheel moving does sound like a plausible explanation.

 

[drf256]

Did you vac test?

If bearings on way, coulda torqued a seal.

Shearing a Stihl key ain't easy.

 

[Adirondackstihl]

 

[TreeLife]

Any update? @Definitive Dave

 

[mdavlee]

Did you vac test?

If bearings on way, coulda torqued a seal.

Shearing a Stihl key ain't easy.

You say that but I've had a dozen with sheared keys.

 

[Definitive Dave]

later this afternoon i should have a chance to take a peak
he wanted a full wrap and skid plate put on the 660 and a 28" bar so I had to spin a chain, and of course i had to set up the new spinner and breaker and he needed a some other stuff so i spent a lot of time "working" after putting away almost 2000 parts, i was too grumpy to keep messing with the 084