Hey everyone, having issues diagnosing my neighbors saw. I have replaced the fuel line, filter, carburetor. The saw will only run on its left or right side with excessive turns on the carb and dies immediately when holding it straight. There is a slight hiss/gurgle I hear coming back through the carb but not every time it starts and dies out. Is this because of intake leak or another vacuum/pressure leak?
Stihl ms210 crank seal or intake leak?
- Thread starter 80Husq61
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You need to vac test that saw.
cedarshark
Addicted to ArboristSite
People do the vac test in different ways. If it fails the vac test, I prefer to pressure the saw up to about 7 psi then submerge it in a tub of water(completely). The bubbles will tell you which side (or both) are leaking. You may find the saw is leaking in other places, ie; intake boot, crank cap seal, etc. Although I do not have a 210, I think it is similar to most Stihl consumer clamshells. If it is an air leak, be prepared to completely disassemble that saw in many cases. I think its easier to replace the seals with the motor out of the case. JMHO.
Dont confuse vac and pressure , both tests need to be done , a marginal crank seal will pass pressure testing but fail vac because the way the pressure pushes the seal lip outward the opposite happens with vac. The underwater is good for pressure not vac. I bet there is a big leak somewhere in there.
cedarshark
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I mentioned a pressure test under water if the saw fails a vac test. The test under water is not meant to replace the vac test...only to locate the leak easiier.
CFM
jack of all trades...master of none
I've use a can of carb clean as a first step diag. Spray lightly around the crank seals, jug base, intake boot ect. While the saw is running. You should see a noticeable idle change when you hit the spot. Just my two cents as a quick step.... Found many a bad crank seals and intake boots this way.
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Never tried it on a saw, but use it all the time for carb. leaks on vehicles. The last saw that I had that massive a leak on would run at half speed at the lowest.
CFM
jack of all trades...master of none
Yea I use carb clean on vehicles as well. Have the big scanner setup to monitor short term fuel trims and then start spraying common failure areas. Always rewarding to see the short terms start returning to normal when you hit the spot
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Well I did notice that the plastic intake piece that butts directly up to the carb with no gasket(great designs there Stihl), is a little warped possibly from previous persons over torquing the nuts. I was able to get the saw running long enough to spray around that area...and it did kill it. The dealer says it passed vac test so I suppose this is the culprit, unless the lip of the intake boot is not sitting in the groove of the plastic housing exactly perfect or is just too out of shape to seal. I have ordered the intake piece, prob should have just gotten a boot as well because that's the last step before I give up. Only thing left is the coil which I tested but could not find the specs for free so not sure if its working intermittently or something.
cedarshark
Addicted to ArboristSite
There is also a metal shim after the gasket and before the intake manifold. Is that present ?
Yes, that is there and doesn't appear to be bent or anything...
cedarshark
Addicted to ArboristSite
The plastic housing(if I understand you correctly) is the housing in front of the carb that holds the air filter. Even if the leak was there,all it would do is allow the saw to ingest unfiltered air. The culprit is somewhere behind the carb. You should probably make or buy another carb gasket. The one I removed from an ms 250 is shot. The old one is in good enough shape to serve as a template.
It has a brand new intake gasket now...the saw starts perfectly at first, idles for a min then dies out. Other times it will only run on its sides but will stay running. I've never had this much issue diagnosing or fixing a 2 stroke before lol. The dealer did a compression test also and it was pretty low at 68 psi...I tested with my harbor freight tester and got 80 lbs but the thing pulls over like it has plenty? The insides look like friggin' new in there sooo idk at this point...if its leaking at the intake housing, that is enough unmetered air to make it run lean and not continue to run I believe?
chainsawman2011
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pull the muffler Ill bet the piston is scored. also take spark plug out and look down with a led flashlight to see exhaust side of cylinder wall. if its not scored bad drop a new piston and rings in it and u should be good to go
No scoring on either side of the piston, normal wash, heck no wear marks to speak of. When it does run it will rev out nicely, and starts easily which leads me to believe compression is not the issue even though those numbers seem low. Sweet old Husqvarna you have!
cedarshark
Addicted to ArboristSite
I think that saw is similar to a ms250 in that there is not a clamp that seals the intake boot to the cylinder. See if there is a plastic shield that clamps over the intake boot and holds it to the cylinder. If that shield is not tight enough to seal the intake boot, you would have a major air leak. To check this will probably mean tearing the saw completely down.
Compression tested by dealer at 68 lbs but the saw is not scored and runs intermittently. Something isn't right here. I don't think a saw will even start at 68 lbs, much less run.
Is there any way this saw could have the wrong rings and piston put in it ?
Compression tested by dealer at 68 lbs but the saw is not scored and runs intermittently. Something isn't right here. I don't think a saw will even start at 68 lbs, much less run.
Is there any way this saw could have the wrong rings and piston put in it ?
The plastic piece is snug over the outside of the boot to the cylinder I made quite sure. I thought it wouldn't run at that low of compression either, but it starts quickly and does not pull over easy, but it can't be ruled out yet either.
IMO, clearly both compression readings are bogus. Probably a combination of probs: not enough cranking, wrong schrader valve. So, I'd disregard it. I'd connect an inline ignition tester and at least rule that out.
