Diagnosis - Stihl

[Four Paws]

Well, I took on the project of a 'tune up' on a Stihl 210C...that has turned into a process of elimination. A lady i work with knows I am into saws, and asked me to tune hers up...new bar and chain, air filter, spark plug, blah, blah. So, I clean it up, open the carb and clean the inlet screen, replace parts, etc. Saw starts and runs great without a bar and chain - revs out, good throttle response, etc. With a 16" bar and 3/8"LP chain, the saw revs up for maybe 1 second, and then bogs - no power. Carb set at 1 turn out L, 1 -1/8 turns out H. Saw performs the same if the H screw is 3 turns out or almost completely seated.

I have:

Cleaned the carb and inlet screen.
Installed a new air filter.
Cleaned spark arrestor.
Inspected piston and rings through exhaust - look fine. This saw starts good, too!
New spark plug.
Replaced clutch springs.
Cleaned the tank vent (black cylindrical type with 7 small holes) and checked for flow.
Checked fuel filter and fuel lines - look like new.
New bar and chain - irrelevant

I have ruled out crank seals - correct me if I am wrong, but this would cause an air leak and make the saw lean out and run good at high rpm. Would also likely hurt the idle.

Other than a complete carb overhaul...I am out of ideas. She is also into this saw $115 now - luckily her son has the same saw, and if hers turns out to be junk, at least he will have lots of new parts for his!

What would cause a saw to be unaffected by adjustments to the H speed screw, and rev up to WOT for only about a second, before bogging big time - like the rakers have been filed too low and you are pushing hard in the cut? Remember, this is at NO LOAD when this is happening, in wood it stalls.

-Josh

 

[Urbicide]

Hi Paws. I was wondering if you can pull the chain around the bar easily by hand.

 

[Four Paws]

Yeah, everything on the saws is checking out A-ok. That is why I am puzzled. You can blip the throttle, and it spins up good, spins the chain, oiler works good, etc. As soon as you go to WOT, the saw revs fast (like it should) then bwaaaaaaaaaaaaaaaah...Bogs down and looses RPM.

 

[SmokinDodge]

Did you blow the carb out with high pressure from an air line? There is a jet that will get messed up if it gets a shot of high pressure air.

 

[CaseyForrest]

Check the spark arrestor screen in the mufler.

 

[Four Paws]

Did you blow the carb out with high pressure from an air line? There is a jet that will get messed up if it gets a shot of high pressure air.

Nope, sure didn't! I know better than that.

Check the sprak arrestor screen in the mufler.

Listed in the first post...already did that.

 

[THALL10326]

Well, I took on the project of a 'tune up' on a Stihl 210C...that has turned into a process of elimination. A lady i work with knows I am into saws, and asked me to tune hers up...new bar and chain, air filter, spark plug, blah, blah. So, I clean it up, open the carb and clean the inlet screen, replace parts, etc. Saw starts and runs great without a bar and chain - revs out, good throttle response, etc. With a 16" bar and 3/8"LP chain, the saw revs up for maybe 1 second, and then bogs - no power. Carb set at 1 turn out L, 1 -1/8 turns out H. Saw performs the same if the H screw is 3 turns out or almost completely seated.

I have:

Cleaned the carb and inlet screen.
Installed a new air filter.
Cleaned spark arrestor.
Inspected piston and rings through exhaust - look fine. This saw starts good, too!
New spark plug.
Replaced clutch springs.
Cleaned the tank vent (black cylindrical type with 7 small holes) and checked for flow.
Checked fuel filter and fuel lines - look like new.
New bar and chain - irrelevant

I have ruled out crank seals - correct me if I am wrong, but this would cause an air leak and make the saw lean out and run good at high rpm. Would also likely hurt the idle.

Other than a complete carb overhaul...I am out of ideas. She is also into this saw $115 now - luckily her son has the same saw, and if hers turns out to be junk, at least he will have lots of new parts for his!

What would cause a saw to be unaffected by adjustments to the H speed screw, and rev up to WOT for only about a second, before bogging big time - like the rakers have been filed too low and you are pushing hard in the cut? Remember, this is at NO LOAD when this is happening, in wood it stalls.

-Josh

Had 210 do that once. Went through it and found da problem. The pulse hose from the cylinder to the carb housing has come almost off. It was on enough to make the saw get enough gas to run but thats all. I took a small needle nose plier and pressed the hose all the way back on the carb housing and the saw ran perfect. Check that pulse hose!!!

 

[Four Paws]

Just went out to the garage quick - the pulse hose checked out. Pulled the handle and plastic off quick, cleaned the hose and checked for cracks, reinstalled - saw started right up, did the same ****.

I saw is NOT getting fuel at WOT - it cant be. Repeated goosing of the throttle will keep the RPMs up, holding it wide open, the saw will bog out again.

The saw has a ZAMA carb - anyone know what model off hand? I forgot to look. I might throw a kit in it tomorrow...then I am through with it! :bang:

 

[Lakeside53]

It's a C1Q-xxx carb.. POS IMHO... Prone to blocking and has a non-replaceable L check valve... grrrr...


Sounds to me like you aren't getting enough fuel TO the carb though...
Take a small weed eater fuel tank (or coffee can, or the fuel feed from another saw), connect it to the carb and hold it three feet above the 210. If the problem disappears, it's not the carb.

 

[THALL10326]

Just went out to the garage quick - the pulse hose checked out. Pulled the handle and plastic off quick, cleaned the hose and checked for cracks, reinstalled - saw started right up, did the same ****.

I saw is NOT getting fuel at WOT - it cant be. Repeated goosing of the throttle will keep the RPMs up, holding it wide open, the saw will bog out again.

The saw has a ZAMA carb - anyone know what model off hand? I forgot to look. I might throw a kit in it tomorrow...then I am through with it! :bang:

Hmmmmmmmmmmmmmmm sounds like that carb is shot Paws. Save your money and forget the kit, most likely still won't run quite right. Do what I do in such deals, pitch it. Before doing so though do one more thing. Those saws are touchy about how tight the carb is screwed on. If its over tighten it will pull the plastic between the mount and create a leak. Loosen it up and snug it gently down and try it one more time before sentancing the carb to death....

 

[Four Paws]

It's a C1Q-xxx carb.. POS IMHO... Prone to blocking and has a non-replaceable L check valve... grrrr...


Sounds to me like you aren't getting enough fuel TO the carb though...
Take a small weed eater fuel tank (or coffee can, or the fuel feed from another saw), connect it to the carb and hold it three feet above the 210. If the problem disappears, it's not the carb.

Prone to blocking...hmmm...I did clean some fines out of the carb when I cleaned the inlet screen. I will try the auxilary fuel tank trick tomorrow - sick of the damn gremlins in that machine. Chasing tail sucks!

Working on that saw, I have determined that newer homeowner saws are just crap - no matter what the brand! I hate how that saw is put together - like one of those silly interlocking puzzles that have to be assembled. The only thing I actually like is the quick disconnect throttle and choke linkages.

Thanks for your help guys! I appreciate it!

 

[Lakeside53]

Hmmmmmmmmmmmmmmm sounds like that carb is shot Paws. Save your money and forget the kit, most likely still won't run quite right. Do what I do in such deals, pitch it. Before doing so though do one more thing. Those saws are touchy about how tight the carb is screwed on. If its over tighten it will pull the plastic between the mount and create a leak. Loosen it up and snug it gently down and try it one more time before sentancing the carb to death....

I take all your "dead" carbs so long as you haven't messed with them!:hmm3grin2orange:

 

[Four Paws]

Hmmmmmmmmmmmmmmm sounds like that carb is shot Paws. Save your money and forget the kit, most likely still won't run quite right. Do what I do in such deals, pitch it. Before doing so though do one more thing. Those saws are touchy about how tight the carb is screwed on. If its over tighten it will pull the plastic between the mount and create a leak. Loosen it up and snug it gently down and try it one more time before sentancing the carb to death....

I'll try loosening it up and lightly snugging it. Then I will try Lake's fuel tank trick. Just want the damn thing to run for her. When she brought the saw over, I offered up my 5100 and let her put her hands on it...was shocked that I paid less than $50 more than that 210C...the feel and build quality of the Dolmar is just that much better that she noticed it right away. Bet she'll have on before this ordeal is over...A new carb would put her into parts over 1/2 what that 210C cost new.

 

[Uwharrie]

Four Paws, Sounds like you put a sales pitch on her. It's easy to sell something you like.

 

[Fish]

Take the carb apart again, remove the mesh screen, and remove the needle
from the other side, then hold up to a light. That passage is likely partially
blocked with debris, blow it out and verify that it is clear, and reinstall.

 

[Kenskip1]

Fp, Fish is on the right trail. My 025 was doing the same thing.I cleaned out all the passage ways on the carb. Still no help. I then removed the diaphram cover and bent the tab so that the diaphram would press further down on the tab and let the needle valve open further.Be very carefull. A small adjustment can make a lot of difference.I do not know how this saw ran before. It may be that the diaphram is loosing it's ability to pull the gas in. An $8 kit should fix this. Hope this helps, Ken

 

[Four Paws]

Well, I went back out in the garage today and messed with that saw. Pulled the carburetor clear down, cleaned it and washed the passages with carb cleaner. Bent the tab on the lever arm that actuates off the diaphragm. Put it all back together and gave it a run. Better...only slightly...and it still runs like shat!

Do you guys seriously think a kit won't remedy this? I am thinking the diaphragm is just weak and stretched out a bit...the saw is 3 yrs. old. My dealer told me that Stihl used 12 different carbs on that saw now

 

[Lakeside53]

I seriously doubt your diaphrams are a problem.. The usual probem is when the metering diaphram is too stiff.

"Bending the arm"... nope... Set it to the correct height...

 

[Fish]

Did you remove the needle,lever,spring, and blow that passage out and
visually verify that it was clear?

 

[stihltech]

lever

Does the inlet lever spin freely on the axle?