new 660 magnum not starting

[chrissthrd]

Just bought my first 660 on thursday.. ran it for about an hour. Shut it off to sharpen chain.. wasn't able to get it started again.. so i was doing some reading and found that i should be able to lift the entire saw up by the starting rope. Tried that and rope pulled right out.( and no my decompression button was not pushed in) im using 89 octane gas with stihl hp ultra oil @ 50:1...... Any ideas on how this could have happened.. it was about 20 deg. Outside and the saw was set-up for cold weather operation... Im stumped... Any help woukd b great so this doesnt happen again.. has anyone had this happen to them?

Thanks
Chrisi

 

[lone wolf]

First check the plug for spark by grounding it on cyl head if good then

Do a compression test and post the numbers if you have no gauge or cant get one
Pull the muffler and look for scoring on piston.

 

[jus2fat]

Just bought my first 660 on Thursday.. ran it for about an hour. Shut it off to sharpen chain.. wasn't able to get it started again.. so i was doing some reading and found that i should be able to lift the entire saw up by the starting rope. Tried that and rope pulled right out.( and no my decompression button was not pushed in) im using 89 octane gas with stihl hp ultra oil @ 50:1...... Any ideas on how this could have happened.. it was about 20 deg. Outside and the saw was set-up for cold weather operation... I'm stumped... Any help would b great so this doesn't happen again.. has anyone had this happen to them?
Thanks
Chrisi

Something is big-time wrong..!!

Take it back to the dealer immediately..!!

J2F

 

[Guido Salvage]

Is the saw "brand new" or "new" to you? If it is new out of the box then this will be an issue for the dealer to sort out.

If it is an used saw pull the muffler and look at the condition of the piston and cylinder. If you see transfer or gouges, then a rebuild is in order.

 

[asdf4240]

Agree with other that if it's a brand new saw take it back to the dealer.

If it's just new to you then it sounds like the decompression valve is open. You should be able to pull it back out. Personally, I've found that once these stihl pro saws are warm the decompression valve is no longer needed. Just turn the switch to on (1 click) and pull. I had something similar happen to me and it was the decompression valve. Might want to check the spark plug too. It could be fouled.

Note: I did read your original post about the decompression valve and this sounds like no compression. Even a badly scored cylinder has some compression.

Good luck.

 

[Beer Gut]

Something is big-time wrong..!!

Take it back to the dealer immediately..!!

J2F

+1

If you want to learn post ?'s here, but warranty saw let them do it. You start pulling it apart and investigating might end up voiding warranty.

 

[lone wolf]

Now the jackass dealer will tell him it was ethanol in the gas that fried it and we all know it was running lean!

 

[Beer Gut]

Now the jackass dealer will tell him it was ethanol in the gas that fried it and we all know it was running lean!

Very likely right but either way let the warranty pay for it..

 

[chrissthrd]

I did try the new plug.. same outcome. The gas couldnt have been mixed any better.. brand new gas can with exactly 5.00 gal of 89 octane and one of the hp ultra bottles for 5 gals. And yes the saw was brand new out of the box.. they did akl of tge tuning adjustments when i bought it. Went though 2 tanks of gas then it crapped out. I took it to a dealer today.. hoping to get it back for the weekend. Does anyobe think the outside temp would have such an effect?

 

[lone wolf]

I did try the new plug.. same outcome. The gas couldnt have been mixed any better.. brand new gas can with exactly 5.00 gal of 89 octane and one of the hp ultra bottles for 5 gals. And yes the saw was brand new out of the box.. they did akl of tge tuning adjustments when i bought it. Went though 2 tanks of gas then it crapped out. I took it to a dealer today.. hoping to get it back for the weekend. Does anyobe think the outside temp would have such an effect?

Colder it is the leaner they run yes.Prob couldnt go out more on the high anyway they have stupid restricters and that my friend could be the cause of the whole thing lets wait and see.Just between us how hard were you running it, non stop in 4 foot oak without time to cool?Was the last cut a big old stump with a dull chain?

 

[lwn9186]

Good you were using Ultra, warranty should be doubled. Do not dump the gas until they tell you it is a problem covered under warranty. Otherwise they could try to say it was straight gas, if that is the problem.

 

[tanker]

I did try the new plug.. same outcome. The gas couldnt have been mixed any better.. brand new gas can with exactly 5.00 gal of 89 octane and one of the hp ultra bottles for 5 gals. And yes the saw was brand new out of the box.. they did akl of tge tuning adjustments when i bought it. Went though 2 tanks of gas then it crapped out. I took it to a dealer today.. hoping to get it back for the weekend. Does anyobe think the outside temp would have such an effect?

I did not realize you could get a bottle of ultra to mix 5 gal. on one bottle.I've only seen the ones for 1 gal and 21/2 gal. Scott

 

[jus2fat]

I did not realize you could get a bottle of ultra to mix 5 gal. on one bottle.I've only seen the ones for 1 gal and 21/2 gal. Scott

Yep..The 12.8 bottle is exactly 50:1 ... Most dealers don't have it..

STIHL 2-Cycle Engine Oil and Lubricants | STIHL USA
(scroll to top of page)

J2F

 

[betterbuilt]

I did not realize you could get a bottle of ultra to mix 5 gal. on one bottle.I've only seen the ones for 1 gal and 21/2 gal. Scott

That's what I was thinking.

 

[betterbuilt]

Yep..The 12.8 bottle is exactly 50:1 ... Most dealers don't have it..

STIHL 2-Cycle Engine Oil and Lubricants | STIHL USA
(scroll to top of page)

J2F

Got ya. Never seen it.

 

[tanker]

Yep..The 12.8 bottle is exactly 50:1 ... Most dealers don't have it..

STIHL 2-Cycle Engine Oil and Lubricants | STIHL USA
(scroll to top of page)

J2F

I've never seen it either,learn something every day Scott

 

[chrissthrd]

Would u like me to post a picture of my bottle? Lol..

 

[betterbuilt]

Would u like me to post a picture of my bottle? Lol..

If this is a brand new saw I'd take it to the dealer.

Is ther any resistance on the pull starter rope. If there isn't you could have a broken starter pawl or a sheared flywheel key.

 

[Anthony_Va.]

So, is the starter cord even turning the engine over? From the way I read it, it sounds like a broken starter pawl or something.

 

[chrissthrd]

Yeah it turns the motor over... I can even pull the plug out, pull the rope and the compression will push my thumb out.. i hope its just somethin stupid.. so i can get my saw back in a timely manor.