Stihl 660 Compression

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a. palmer jr.
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Apr 8, 2007
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I rebuilt a Stihl 660 with an AM piston and cylinder using the usual methods, using the cylinder base gasket and the saw seems to have too much compression. When I try to start it it kicks back and pulls the starter handle out of my hand even using the compression release which works. Is this normal or what? I used some oil for assembly but I didn't use a big bunch, just a little on the rings and cylinder and a small amount on the crank rod bearing and wrist pin. I tried drop starting it and it did the same thing. Any thoughts?
 
a. palmer jr.
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I've tried drop starting it and it pulls the rope out of my hand. I tried a minute ago and got it to hit with the choke on but when I released the choke it started the kicking back again. Part of my problem is my hand is getting a bit weak because of all the pulling on these saws I've done. I'm gonna take it to a younger guy this evening and see if he can pull it through. Every time I get one of these bigger Stihls I wince because I know what's coming up. I traded my 044 off just because of this.
Does it spin freely with the plug out?
Yep, it turns over okay with the plug out but when you push the de-comp in with the plug in it pushes it right back out when you pull the rope. I'm pretty sure I didn't drop anything in the crankcase except a bit of oil when I oiled the rod bearings.
Have you ran it or can't get it to start?

Are you drop starting it?
I've never ran it. It was brought to me with low compression and I just put a p/c in it. The assembly went pretty well so I figured it would fire right up.
 
jchin

jchin

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Warwick, RI
I've tried drop starting it and it pulls the rope out of my hand. I tried a minute ago and got it to hit with the choke on but when I released the choke it started the kicking back again. Part of my problem is my hand is getting a bit weak because of all the pulling on these saws I've done. I'm gonna take it to a younger guy this evening and see if he can pull it through. Every time I get one of these bigger Stihls I wince because I know what's coming up. I traded my 044 off just because of this.

Yep, it turns over okay with the plug out but when you push the de-comp in with the plug in it pushes it right back out when you pull the rope. I'm pretty sure I didn't drop anything in the crankcase except a bit of oil when I oiled the rod bearings.

Mr A. Palmer Jr, I have a Stihl 044 that pulls starter handle out out my hand also. That is why it sits on the shelf. I am 64 years old with a bad weak arm. Jason is fixing my stihl 064 so I can use it again.

You may try this to see if it would help. Take out your stihl decompression valve. Replace it with a decomp valve from a Dolmar 7900 or Husqvarna 372, 385, 390. These have a larger bleed off hole. The stihl decomp valve have a small bleed off hole. Try it, you got nothing to lose.
I should sell my 044........
 
spudulike
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Apr 8, 2009
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Herts UK
The elasto start handle will definitely help, it is also possible the flywheel to coil gap is a little too tight and has advanced the ignition a few degrees giving rise to this kickback - seen it before. Try a slightly larger gap.
As someone else said, once the rebuild oil is cleared, compression will drop a bit and it will be easier to pull over.
 
sugarbush

sugarbush

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you could try a deco from another saw, not stihl, blue knob used on dolmar, husky, ect. -- they don't close as easily as stihl's. the saw may also be out of time. or if someone else worked on it before you it may have the wrong flywheel/coil combination.
 
jmssaws

jmssaws

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Those elastostart handles aren't that great, IMO. They feel sloppy to me and I don't seem to get a nice crisp pull with them. Plus they are like $20+ bucks.
I have big hands and there to big for me to get a good grip on,I never have liked them. Plus if you break the rope your out another 20$
 
albert

albert

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You can try loosening the spark plug about 1 turn, if the threads are good, to bleed off some compression to get it started and burn off the extra oil. You shouldn't need to run it very long like this maybe a minute or 2.
 
a. palmer jr.
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I took the saw to the younger guy and he got it started for me. I held down the comp. release while he pulled and it fired right up, and smoked a bit, then I adjusted the idle and it's all done. I know these are expensive saws but I'm also glad it's not my saw. I think I prefer my 361 to the 660. While I was there they gave me another one to rebuild..
 
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