Stihl MS271 Puzzler

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cookies

ArboristSite Guru
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Nov 26, 2020
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885
Location
Crawfordville
a wire wheel, wire brushes, razor blade to remove the old sealant, use 2 cycle oil and a little paint brush to pre lube bearings and the seal lips. shouldent need a install tool on a clam shell for seals, they just push onto the crank and get sandwiched into place by the case halves.
 
waffenschmidt

waffenschmidt

ArboristSite Lurker
Joined
Oct 11, 2021
Messages
13
Location
Washington
a wire wheel, wire brushes, razor blade to remove the old sealant, use 2 cycle oil and a little paint brush to pre lube bearings and the seal lips. shouldent need a install tool on a clam shell for seals, they just push onto the crank and get sandwiched into place by the case halves.
Great, that all makes sense. Thank you.
 
Vitex

Vitex

New Member
Joined
May 8, 2019
Messages
1
Location
New Zealand
I have an MS271 with maybe 20 hours on it over 4 years. Last time I used it, after running fine for about 20 minutes, it bogged down and then stopped halfway through an easy cut. I was able to restart it and finish the cut, but it stopped halfway through the next cut. It hasn’t run since.

It had some 3-year old gas/oil mix in it (with stabilizer, but still old) so I figured I had gummed something up and I did this:
  • Dumped the old gas and refilled with pre-mixed.
  • Pulled the spark arrestor and verified it was clean.
  • Blew the dust off the intake filter with compressed air.
  • Replaced the spark plug and verified that I had spark.
  • Cleaned the gas pickup/filter with carb cleaner (including soaking overnight).
  • Took apart the carb but found nothing gummy or anything that looked fishy.
  • Replaced the carb with a new one.
  • Checked the impulse line (through the intake boot) and verified that it’s clear.
  • Hooked a clear plastic syringe up to the gas line carb connection, pulled out a couple ounces of fuel and saw no bubbles. Was able to push about half of it back into the tank and then needed to open the fuel cap to relieve pressure, so it seems there are no leaks in the line and the relief valve on the tank works.
It’s just dead when I try to start it. It must not be getting fuel, but I can’t figure out why. A couple times after putting it back together to test, it fired for a few cycles that was it.

Any thoughts about what to try next? I don’t have a compression tester or any way to verify that the crankcase is sealed.

I don't have much experience with small engines, although I pretty much understand how stuff works. Still, I could very well be missing something that would stick out to someone with experience.

Sorry for posting this as my first post, but I found you guys when looking for ideas and people here obviously know what they’re talking about.
Try starting it by squirting a little gas straight into the carb. That'll rule out a carb problem - if it runs, you know the carb is bad. Then you can rebuild the carb, or you can replace the whole carb. Newer stihl carbs have a problem with leaking round the accelerator pump (cough made to fail cough).
 
Okie294life

Okie294life

Small engine jackwagen.
Joined
Jun 25, 2018
Messages
476
Location
Arkansas
I have an MS271 with maybe 20 hours on it over 4 years. Last time I used it, after running fine for about 20 minutes, it bogged down and then stopped halfway through an easy cut. I was able to restart it and finish the cut, but it stopped halfway through the next cut. It hasn’t run since.

It had some 3-year old gas/oil mix in it (with stabilizer, but still old) so I figured I had gummed something up and I did this:
  • Dumped the old gas and refilled with pre-mixed.
  • Pulled the spark arrestor and verified it was clean.
  • Blew the dust off the intake filter with compressed air.
  • Replaced the spark plug and verified that I had spark.
  • Cleaned the gas pickup/filter with carb cleaner (including soaking overnight).
  • Took apart the carb but found nothing gummy or anything that looked fishy.
  • Replaced the carb with a new one.
  • Checked the impulse line (through the intake boot) and verified that it’s clear.
  • Hooked a clear plastic syringe up to the gas line carb connection, pulled out a couple ounces of fuel and saw no bubbles. Was able to push about half of it back into the tank and then needed to open the fuel cap to relieve pressure, so it seems there are no leaks in the line and the relief valve on the tank works.
It’s just dead when I try to start it. It must not be getting fuel, but I can’t figure out why. A couple times after putting it back together to test, it fired for a few cycles that was it.

Any thoughts about what to try next? I don’t have a compression tester or any way to verify that the crankcase is sealed.

I don't have much experience with small engines, although I pretty much understand how stuff works. Still, I could very well be missing something that would stick out to someone with experience.

Sorry for posting this as my first post, but I found you guys when looking for ideas and people here obviously know what they’re

when you say new carb is it OEM or China? If the latter may go ahead and try again yeah…they’re crap half the time.
 
waffenschmidt

waffenschmidt

ArboristSite Lurker
Joined
Oct 11, 2021
Messages
13
Location
Washington
Just to wrap this up, I finished the top end replacement and it starts and runs fine. Still have a few questions, but I'll do some more research and maybe start another thread if I can't figure it out.

Thanks again, all, for your help.
 
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