Starting problem with my Stihl 084

[Appletree]

I bought a rather ancient 084 with 41" bar a couple of weeks ago. The saw runs well, stops when it should etc once you can get it going. During the past couple of weeks I must have started the saw about 20 times to adjust the carb and to make sure that everything works as it should. The saw starts fine most of the time but every now and then, as I pull the starter cord, it fires and snaches the cord/handle back with such a force that it almost rips my arm and fingers off ... its pretty painful when that happens. This fault is intermittent and the saw then 'mends' itself after a while. Can anybody enlighten me as to why the saw behaves in that manner and what the cure is? Cheers,

 

[Dibbs]

Pull harder!
With a saw that size you should be pulling every time like you are trying to pull your first born out of the path of a 30 ton truck!
Every time you pull without the engine starting check the decomp valve is still pushed in.

The only other option I can think of is the woodruff key is twisted or sheared which is allowing ignition of the plug "off time", highly unlikely though.

 

[Dadatwins]

Timing issue. The 084 has 2 slots on the flywheel to set for 2 different coils, Lakeside gave me the info to get mine going since I had it set in the wrong slot and it bucked like you describe. Check the flywheel and if it has has 2 slots try it in the one that it is not in now.

 

[RavensRoost]

Appletree, might be the method you are using to start it. Try gently pulling starter rope to get piston near TDC (firm resistance), relax rope to let rope go back into recoil, then with your foot in the trigger handle pull "with authority" as they say.

 

[Appletree]

Thank you Dibbs, Datatwins and Ravensroost for your answers.
Armed with this new found knowledge, I want to go out and get the saw going again but can't quite summon enough courage to do that just yet...my right hand is still hurting after 2 days and I am not so fearless now as I once was a few days ago about pulling that starting handle. May be I should look up what this 'woodruff key' thing is while I'm convalescing instead. I wonder if someone makes a 12v starter motor, or some sort of foot operated starter thingy (like the ones they have on motor bikes) for these gorilla sized chainsaws. Many thanks for your answers once again.

 

[Dadatwins]

Woodruff key is proper name for flywheel keyway. Pull the flywheel and you will find it on the shaft.

 

[Appletree]

Thank you chaps

Feeling stronger, I took my 084 out into our back garden this afternoon and .... had the engine ready at TDC, like RavensRoost said, and pulled the cord like pulling my first born out of the path of a 30 ton truck like Dibbs told me to...and guess what....it ROARED 084 ROAR on first pull and did the same on subsequent 4-5 pulls. I didn't have to change coil position but Datatwin's tip is a very clever one so I must try not to forget it. I wonder why they have two slots - could this be to do with milling or something? Talking about milling, I bought my 084 so that I can cut a very thick one piece table top using an Alaskan Mill (48"). This has been an ambition of mine ever since I saw a 700 year old table(one piece top) in a pub in Laycock (in Cotswold). The table was incredibly thick and almost black if I remember correctly. That was more than 20 years ago but I still sometimes think about the table... the person who made it, pints drunk and stories told at the table etc. Anyway thanks chaps, it looks like you solved my problem. By the way, I think this is a terrific site ... I never posted anything on the net before and I feel as if I've just won something!
All the best,
Park

 

[Dibbs]

Glad you have it sussed and your fingers are getting better!
Be sure to post a few pics of your milling project for us all to drool over.