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Stihl Wood Boss, kicks, doesn't run

Started by tomwalz, April 29, 2019, 09:14:18 PM

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tomwalz

Stihl 028 Wood Boss.

I am an experienced industrial machine maintenance tech. This is an occupation where others think I know it all. Truth said, I don't. This saw is my undoing.

I moved to the country, built a wonderful free-standing rocket stove, and use it as supplemental heat. Friends gave me chainsaws, all of them dead... I now have 5 saws, and friends, happy to have more space.

Oddly, I got the cheesy, cheap ones running great. 

The two better ones, the most powerful ones... nadda. Let me start with this Wood Boss, from the 80's, slot head screws, made in Germany. 

A friend gave it to me (free is for me). It sat for quite a long time, but he told me it only has about 20 hours on it.

I did what one would expect, checked spark, it was good. The carb was gunked badly. Bought a cheap Chinese equivalent, the saw fired up and I used it, putting a couple hours on it. Then it died. It hasn't run since.

I did replace gas lines, fuel filter, before new carb.

I thought the spark looked weak and read a forum that suggested a pointless coil. Installed it. It tested out fine. Still... the saw would kick, but not run.

I watched every YouTube on 2 stroke tool carbs... eventually coming across very well produced and thorough ones, giving me the illusion I was now a trained expert.

I got a rebuild kit for the original carb. I removed the Welch plug and checked every orifice and passage. All good. I took the new coil off, went back to the original, put a driver on the flywheel, gave it a good spin, slow and fast, and spark is really good. 

Results were the same. It kicks, doesn't run. Tried the carb adjustment screws from lean to rich, nadda... always the same. When I pull the plug, its wet... like there's no spark, but the spark looks good when I check it with the plug removed. Muffler is clean, no buildup.

Any suggestions... HELP! What did I miss? 

Once this gets fixed, it's on to a 1978 Partner R517...


dougand3

You've done a whole lot....

Is saw trying to rip the pull handle out of your hand? Makes me think mis-timed. Key located properly? A ballpark timing check is when at TDC, magnets should be just past coil legs.
Husky: 372xt, 272xp, 61, 55 (x3)...Poulan: 315, 4218 (x3), 2375, 2150, 2055, 2000 (x3)...Stihl 011AVT...Homelite XL...Saws come in broken, get fixed or parted, find new homes

Inaotherlife

New spark plug. Just to eliminate the possibilty. 

Pull the muffler so you can see the piston and cylinder and check for scoring.

Then If that looks good, a compression check if you can.

tomwalz

Both worth a shot. The flywheel has never been removed, will give your simple test... occassionally the pull rope is like its anchored within.... won't budge.

I can't see why the plug would be bad after what little time is on this saw... still... I'm at a loss here... going for it. Compression is killer. Got a glimpse at the piston when I pulled the muffler... looked like new.

Thanks

tomwalz

I'm a noob at this site. Haven't figured out how to reply to each post, or post a photo... some things take time.

Dougand3, I took a pic, magnet is about a half inch passed coil leg at TDC.... is that good?

luap

I too was in industrial maintenance and learned to question everything any time some one said: "its only run x hrs." or whatever condition they attribute to the machine problem. You never know who was in there in-between. My first impression with a wet plug it is flooding and almost hydolocking the piston, making it hard to pull. Since you had the carb apart, it is easy to get the gasket and diaphragm on in the wrong order or the diaphragm with the metal disc upsiside down that affects the opening and closing of inlet valve, causing it to flood. I would remove flywheel and check key. Shine up magnets and end of coil arms. reset coil to flywheel clearance, approx. .010", approx. thickness business card.  Since the replacement carb worked although  not very long, I would look for any possible air leak, intake manifold. loose screw, internal condition of muffler, blow out air cleaner. You have to approach this as though you don't know any history of this saw                 

dougand3

Quote from: tomwalz on April 30, 2019, 12:22:36 AMoccassionally the pull rope is like its anchored within.... won't budge.


That sounds like hydrolock, as luap alluded to with carb flooding.

Quote from: tomwalz on April 30, 2019, 12:45:41 AMmagnet is about a half inch passed coil leg at TDC.... is that good?


Sounds about right.

I'd try a new carb - $10 online.
Husky: 372xt, 272xp, 61, 55 (x3)...Poulan: 315, 4218 (x3), 2375, 2150, 2055, 2000 (x3)...Stihl 011AVT...Homelite XL...Saws come in broken, get fixed or parted, find new homes

tomwalz

Thanks to the maintenance tech pat on the back... yeah, I've seen nightmares... heavy weldments broken... nobody know anything.... getting hit with 220 3 phase because someone removed protection... big fun... many stories.

Anyway, checked the diaphragm, it's right. I need to get the tool for pulling the flywheel. Tried my bicycle crank puller... wrong thread.

Going to mess with it some more, if no success, going to work on the Partner... which has amazing amount of spark. I've not seen spark this powerful on some cars. Carb rebuild is in order. When it ran, it would bury your feet with sawdust in seconds. 

Onward! Thanks.

zimraphail

Pull flywheel nut, loose thread flush with end of crankshaft, apply a little pressure with large screwdriver or little bar under flywheen and wrap crnk nut wit a deadblow hammer! One or two blows normally pops them right off!

luap

One saw that I replaced the carb on I could not get running. Would start quit, flood, plug all wet. Tried adjusting Hi speed screw, seemed to improve a little but it had the plastic limiters on hi lo screws. Removed the limiters and in no time was able to fine tune the saw.

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