Stihl chainsaw

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  #1  
Old 10-02-08, 11:21 AM
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Stihl chainsaw

I bought a Stihl chainsaw MS 180 (USED)The problem is it is firing ,and I put fuel in the plug hole but it want burn that fuel off.Can anyone help?
Jackman44
 
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  #2  
Old 10-02-08, 12:58 PM
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You have a few possibilities. First change the plug. You may have a bad spark plug = can't fire in compression. Then purge the fuel/air from the cylinder = no spark plug, full throttle, no choke - then spin the engine over about ten times. Then put about a teaspoon of fuel mix in the plug hole and spin the engine over a couple of times (only a couple of times). Then put the plug back in, half throttle, no choke and see if it will fire. If you still get nothing...

You could have poor compression, or the flywheel key has sheered and the engine is out of time. The latter usually isn't the problem, but it can happen.
 
  #3  
Old 10-02-08, 02:28 PM
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chainsaw

I am soaking the flywheel overnight,and will try to take it off tomorrow to see if the pin is sheered.
Jack
 
  #4  
Old 10-03-08, 06:35 AM
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Key

I removed the flywheel.It looks like the key is built into the flywheel.I have never seen this before.Would anyone know if the MS 180 Stihl build their saws this way?
Jack
 
  #5  
Old 10-03-08, 06:44 AM
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There are some other makes that have that design. In your case, if the key and the flywheel is properly positioned on the crankshaft keyway, everything there is fine.
 
  #6  
Old 10-03-08, 06:58 AM
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key

There is very little of the key left.Not enough to hold in place.
Jack
 
  #7  
Old 10-03-08, 11:06 AM
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That's not good. You might try to locate the flywheel on the crank with what left of the old key as a reference, then torque the flywheel nut to specs. It may be enough to hold it. If not, you'd have to replace the flywheel.
 
  #8  
Old 10-04-08, 07:33 AM
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saw

Marjobj,I did what you said but want fire.A ? if the saw has no compression wouldn't it fire the fuel that is put on top of the piston?
 
  #9  
Old 10-04-08, 08:46 AM
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No, I'm afraid not. Without good compression it won't fire and you'll wear your arm out pulling on that cord - guaranteed.

When you have the plug in it and you pull on the cord, everytime the crank comes around you would feel a lot of resistance on the cord. If it turns over easily = no compression = won't fire or start.

Pull off the muffler so you can see inside the cylinder and check the inside of the cylinder and piston for scoring. If there is scoring that's probably where your compression went.
 
  #10  
Old 10-04-08, 08:57 AM
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saw

I put the lever in the run position,and when I pull the cord the engine sounds like it has compression.This saw has the easy start.I pulled the muffler and there is scoring but it still sounds like it has compression.I guess I will have to buy a compression gauge.I have 130.00 in the saw.I don't know what they cost new but I would guess 250.00.
 
  #11  
Old 10-04-08, 03:42 PM
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Try this - it's pretty elementary and isn't altogether an indication of what the level of compression is, but pull the plug and seal the plug hole with your thumb. Then pull the starter cord. If you don't have enough compression to blow compression past your finger, you don't have the compression you need to fire the engine.

There is a large range of compression levels past this point, but it will give the lower level you need. For an accurate reading you'll need the tester. You can usually borrow or rent those from an auto parts store.

I'm afraid, with the scoring you've seen through the exhaust port, lack of compression is the problem. The compression isn't something you can tell by sound. You would have to go by the resistance on the pull rope.
 
  #12  
Old 10-05-08, 06:28 AM
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Compression

Thanks for all the help.I have ordered a short block from ebay.That should take care of the problem.
Jack
 
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