Stihl chainsaw runs like crap

[Cam]

Hey cheers Hayden, i don't need any at the moment, but im good at breaking stuff so i suppose it wont be long!

You wouldn't mind posting a pic of those saws on my thread would ya? Just out of curiosity, thanks mate : - )

Fair enough blue, if the shipping wasn't so steep I would be more than happy to do that for you!

Wouldn't bother restoring it, looks in alright nick and it isn't of any vintage by the looks of it, just get it running mint for him.

Whats the progress been like on it?

 

[sexyvicta]

I would totally disagree, my 400 2 stroke was running on almost pure 2 stroke oil as it had settled in the carb. That was puffing out blue smoke for Africa.

Jeremy.

yeh iduno. I know what you're saying two stroke blue smoke. But my chainsaw and my hedge trimmer which i use once in a blue moon will puff out a lot of white smoke once they fire after like 10 pulls. I assumed due to crankcase being full to the brim with unburnt mix. White smoke clears once i've run them at full throttle for 30 seconds ish. After that the start up normal for the rest of the day and yeh just a maybe little blue smoke but hardly any with the oil i run. Only see it if i leave the engine idling for a couple minutes then rev it up

iduno

 

[HellSpawn]

Check the clutch & chain brake assembly, by the looks of those videos, the brake actually looks to be engaged.
White smoke could possibly be from the clutch burning up. You do say it rotates freely (a full revolution?)

Check and see if the drive-gear has split from the clutch drum.

I'm out of ideas now.

 

[sideways]

Hey cheers Hayden, i don't need any at the moment, but im good at breaking stuff so i suppose it wont be long!

You wouldn't mind posting a pic of those saws on my thread would ya? Just out of curiosity, thanks mate : - )

No worries mate, I'l grab some pics some time this weekend. They aren't saws, one I got just the engine from a scrap metal yard, the other was a chain saw with pretty much everything stripped off it. The 2 engines are almost identical. The second one was a Mac 110 from memory. Cast aluminium panels are nice hay!

 

[Badot]

Have you tried playing with the spark gap at all?

Maybe check the kill switch too... if there's some way to easily disconnect it, try disconnecting it. Make sure you're ready to stop it if need be though. I've had bad kill switches cause strange problems for me.

And you've checked to make sure there's nothing wrong with the clutch, I take it?

And not sure about this one, but could glazed cylinder walls cause these symptoms?

 

[Bluethunder3320]

heres what i have done so far:

• removed bar and chain
• removed muffler
• checked plug, looked ok. maybe ill regap.
• carb is totally clean
• put in fresh gas
• put in bar and chain oil
• removed air filter
• checked cylinder

i hope im not missing anything. spark arrestor is totally clogged up.

its pouring rain and thundering, i havent been out in a couple days. also doing exams in school......

 

[sexyvicta]

heres what i have done so far:

spark arrestor is totally clogged up.

that will effect performance but prob not the cause of your problems. Clean the mesh out anyway and see what happens. Some guys remove spark arestor from exhaust completly as they reckon they gain extra power. I myself cant see any noticable difference and leave them in and clean 'em once in a while. Safety first:arf:

but yeh in your first vid it does sound like the chain break is engaged...

i would put a fresh plug in. cj7 or cj8? and then try and adjust the carb

 

[HellSpawn]

Removing the bar & chain is not enough, Make sure the brake assembly is not hanging up on the clutch drum or anything of that nature.

 

[Bluethunder3320]

Removing the bar & chain is not enough, Make sure the brake assembly is not hanging up on the clutch drum or anything of that nature.

well i removed the whole cover on the side of the clutch too... if you look carefully you can see the actual clutch.... it would make sense thats it though......

 

[Bluethunder3320]

that will effect performance but prob not the cause of your problems. Clean the mesh out anyway and see what happens. Some guys remove spark arestor from exhaust completly as they reckon they gain extra power. I myself cant see any noticable difference and leave them in and clean 'em once in a while. Safety first:arf:

but yeh in your first vid it does sound like the chain break is engaged...

i would put a fresh plug in. cj7 or cj8? and then try and adjust the carb

its not mine and im only getting 10 bucks so ill call him this weekend once i mess with it tomorrow or saturday, when it stops raining........

 

[bighead]

How do you know the carb is clean? did you clean it? or does it look clean?

 

[Bluethunder3320]

i removed all the gaskets that were in tact, and there was really nothing to clean because the carb has been sealed off inside a chamber under the air filter, and the needle moved fine with my finger, all the jets were not clogged.

i could have cleaned it and nothing would change.

EDIT: this thread has almost 1K views???

 

[wall gator]

JUST CLEAN THE CARB!!!! YOU'VE BEEN TELLING EVERYONE IT WAS DONE.....START WITH CARB,,,,THEN WE'LL GO FROM THERE,

 

[bighead]

i removed all the gaskets that were in tact, and there was really nothing to clean because the carb has been sealed off inside a chamber under the air filter, and the needle moved fine with my finger, all the jets were not clogged.

i could have cleaned it and nothing would change.

EDIT: this thread has almost 1K views???

You never know. time for some lemon juice. It will take you 30 minutes to clean that carb spick and span.

 

[Cam]

Im telling you guys its the automatic transmission fluid!?

 

[sideways]

Im telling you guys its the automatic transmission fluid!?

Na mate, it's gotta be the muffler bearings!

Seriously though blue. Clean the carb!! I don't care if it looks clean, I bet you it isn't! It's best to get a proper rebuild kit, over time the diaphragms go hard (or soft, if you use ethanol fuels) and make it run like ****.

So, answer these.

1)Does it rev higher at around 3/4 throttle?

2)Can you feel the bottom end compression(ie, can you feel the air fuel mix compress hard when the the piston goes down)? Have you tested the crank seals? Do you know how to?

3)Are the points/dwell (if it has them) set correctly (I guess you don't know how to do those though)?

4)Is the exhaust port all blocked up?

5)How's the spark plug?

6)Did you replace the carby to barrel gasket?

7)Is the air filter clean?

8)Are the passages to the air filter unblocked?

9)Have you tried tuning it using the high and low speed screws? (like rustydog said)

Ect ect...

 

[Bluethunder3320]

1)Does it rev higher at around 3/4 throttle?

______no.

2)Can you feel the bottom end compression(ie, can you feel the air fuel mix compress hard when the the piston goes down)? Have you tested the crank seals? Do you know how to?

______yes it has plenty of compression, i dont know how to check crank seals, would WD-40 work like on intake gaskets?

3)Are the points/dwell (if it has them) set correctly (I guess you don't know how to do those though)?

______i know how to set points, but its solid state, and the coil gap is good, i checked.

4)Is the exhaust port all blocked up?

________spark arrestor was blocked, i have removed.

5)How's the spark plug?

________spark plug is nice and clean and correctly gapped (not running lean though)

6)Did you replace the carby to barrel gasket?

________no i have not. i might have a spare ill go look.

7)Is the air filter clean?

_______semi-clean, but ill clean it out more. i ran it w/o filter to test it as in the videos.

8)Are the passages to the air filter unblocked?

_______no blockage

9)Have you tried tuning it using the high and low speed screws?

________i have tried resetting them a few times and no setting works.



i got some work to do, ill be back.


now, WHERES RUSS????

 

[Cam]

Na mate, it's gotta be the muffler bearings!

Thats what that bloody rattling noise is!

Have you checked the valve springs blue?

Back to helping.. I suggest blowing it into a million pieces and thoroughly cleaning and reassembling, then if you don't succeed, douse it in a couple of litres of petrol and set fire to it

 

[Bluethunder3320]

if you don't succeed, douse it in a couple of litres of petrol and set fire to it

i also have a bottle of r/c glow fuel. nitro methane

that costed me $40 a gallon.... top fuel is expensive. sold my r/c buggy, only got 100 bucks for it.


i put the exhaust back on, hopefully test tomorrow!!!!

 

[robbie]

After watching your videos, I think the saw is not getting enough fuel. It appears that the oil mixture is rich enough because of the white smoke, but when a saw just refuses to rev up with no load you can bet there's not enough fuel coming in.

You would be wise to inspect the diaphragm as well as the lines. Bad diaphragm means bad fuel pumping. Cracked line will cause air bubbles and lean fuel mixture.