Stumped with an Ms210

[Stihlcranking]

Have a Stihl MS210c. Seems like it is always giving me carb trouble. Had it sitting this summer, and needed to get ready for the fall for some firewood . Dumped the gas, took the carb off/apart and cleaned it. Cleaned the plug, and the air filter was good. The mesh screen was also cleaned.

I reset the L and H screws to the recommended (3/4 turn off H and 1 full turn of L). Can't get the LA screw set because it stalls before I can adjust.

When I first start it up it fires right up. I can rev it full throttle, and when i let off the throttle it idles for a few seconds, and dies. It won't restart. Let it sit a while, and the same thing happens over again.

What am I missing? I haven't had this kind of issue before...

 

[HarleyT]

Look closely at the fuel line.

 

[SteveSr]

Can't get the LA screw set because it stalls before I can adjust.

Give it a couple of turns before your restart it! Saw doesn't have to be running. Worst case it will just idle too fast.

What am I missing?

How old is the gas... From the pump? Try some brand NEW from the pump. If you go to a dealer the FIRST thing they do is dump the gas and put in fresh. Only if that fails will they look further.

Or as Harley said... the fuel lines on these tend to crack between the top of the tank and the handle where it makes a sharp bend.

 

[Stihlcranking]

The gas is literally brand new with new oil mixed in.

I'll try turning it a couple turns in the am. However, before it stalled the chain was turning very quickly around the bar. So turn it even more?

If the fuel line is cracked, is that why it won't restart after it dies?

 

[SEAM]

Accelerator pump in the carb....

 

[SteveSr]

The gas is literally brand new with new oil mixed in.

Check.

If the fuel line is cracked, is that why it won't restart after it dies?

The carb may have sucked air instead of gas. It may restart if you choke it again (cold start procedure).

Will the saw stay running at high speed and/or cut at WOT?

 

[Sam R]

Symptoms point to a fuel delivery issue.
If you've got a mityvac and some fittings for your fuel line & carb you can test the individual components and find the fault. If not you're basically just guessing.

 

[Stihlcranking]

So, went ahead and did a carb rebuild for it just to be safe. And replaced the fuel line in case there were some cracks.

Fill it back up with gas and it wont do anything now.

Seam mentioned the accelerator pump?

 

[HarleyT]

Take off the muffler and look at your piston,
to start with.

 

[Stihlcranking]

Took off the exhaust. What am I looking for in particular? Looks like there is some gas coming out of it, but I'm not sure if that's normal. Attached 2 pics, one of the back of the exhaust, and one of the piston. Not a lot of visibility though.

When I got home from work it started and idled VERY erratically until it stalled. Never was able to give it gas as it would start to bog immediately. Once it stalled, it would only start for a couple seconds and stall again.

 

[Sam R]

We'd need to see more of the piston, the ring and whole exhaust side of it.

Wouldn't be a bad idea to look closely at your spark plug, make sure your impulse line isn't leaking. If you check that, and it's all fine - I'd really start suspecting there is an air leak somewhere downstream of the carburetor.

 

[HarleyT]

Looks like there is some gas coming out of it

Well, then it is likely flooded at the moment.

I suggest looking at the piston condition first, before starting any Saw Saga......
Try to get a pic of the piston @ the ring area.

 

[kr5258]

I'm leaning towards a leaking welch plug. With the carb apart, remove the low speed screw and squirt carb cleaner (with tube on the nozzle bottomed into screw hole) and watch welch plug as you squirt. If you see leaking, run a drop of fingernail polish around the edge of the plug to seal.

 

[Brent Adams]

Change the spark plug, after youve verified the piston isnt scored or carboned over. Eliminate those two easy issues. Even if you show fire at the plug with ot grounded to the cylinder, change it.

 

[SteveSr]

So, went ahead and did a carb rebuild for it just to be safe. And replaced the fuel line in case there were some cracks.

Did you use Stihl/Zama OEM parts or aftermarket?

Seam mentioned the accelerator pump?

I don't think that your carb has an accelerator pump. Even if it did it is likely non-serviceable.

How much is a new OEM carb from your dealer?

 

[dmb2613]

about $33.00

 

[SEAM]

Not sure if the carb on your MS210 has an accelerator pump... But if the engine does not start at all after the carb rebuild (what parts did you replace) it either gets no fuel (plug dry) or too much fuel (plug wet). If the plug is wet the carburetor might be leaking internally (inlet needle, welch plug, etc.). A dry plug would mean the carb gets no fuel or does not work at all.

At this point it would be best to find someone near you with a spare working carburetor to find out if the problem is your carb or your saw...

 

[Stihlcranking]

I used stihl/zama carb rebuild kit. Bought it at the local stihl dealer/warranty repair shop.

I'll dig into the cylinder today to get a look at the piston and swap the plug as well.

If both of those are good I may just buy an all new carb and put it on there just to be done with the issue.

 

[SteveSr]

I'll dig into the cylinder today to get a look at the piston and swap the plug as well.

I wouldn't tear it apart as you pretty much have to tear the whole saw apart for complete access to the cylinder. You should be able to clearly see any issues just by pulling the muffler.

I have seen these leak around the clam shell pan seam. You might want to check/re-torque the 4 cylinder/pan/main housing bolts on the bottom of the saw. However, this is not likely your problem.

 

[Sam R]

I used stihl/zama carb rebuild kit. Bought it at the local stihl dealer/warranty repair shop.

I'll dig into the cylinder today to get a look at the piston and swap the plug as well.

If both of those are good I may just buy an all new carb and put it on there just to be done with the issue.

If you've got the original carb still on it - I'd like to add, the welch plugs on those can develop leaks because the sealant they used back then doesn't hold up to ethanol.