Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Stihl => Topic started by: BHB on July 23, 2016, 09:15:07 am

Title: Stihl MS 170 won't start hot
Post by: BHB on July 23, 2016, 09:15:07 am
Saw starts good when cold but after running for about 20 to 30 minutes it won't start after it has been shut off. Tried with choke off , choke on & with choke half on it seems like it wants to start but doesn't. New fuel filter , fuel line, air filter , carb & plug have been installed.
Title: Re: Stihl MS 170 won't start hot
Post by: Cut4fun . on July 23, 2016, 11:06:50 am
It wont restart after you shut it off or does it shut off on its own?

Title: Re: Stihl MS 170 won't start hot
Post by: BHB on July 23, 2016, 11:57:17 am
After I shut it off.
Title: Re: Stihl MS 170 won't start hot
Post by: Cut4fun . on July 23, 2016, 12:24:16 pm
Try this. Open your L side up a 1/4 turn going counter clockwise

Sending you stihl 170 IPL in PM too.

These little saws are known for carb issues. Also only come with the L side and I idle. No H sides.
But you can buy a new replacement carb with H and L for around $25.
Title: Re: Stihl MS 170 won't start hot
Post by: Cut4fun . on July 23, 2016, 12:38:17 pm
Another WAG. When you get it running on a cold start  and it is idling good on its own. Try rolling the saw to its side and see if you notice any difference in idle. Then roll to other side making note of differences of idle going up down stalling etc.
Title: Re: Stihl MS 170 won't start hot
Post by: BHB on July 23, 2016, 06:24:33 pm
Will try both . Thanks.
Title: Re: Stihl MS 170 won't start hot
Post by: BHB on July 23, 2016, 07:08:54 pm
Started saw cold & left it idle. Rolled saw from right side to left side. No noticeable change in idle.
You stated to turn the L screw 1/4 turn counterclockwise. I only see one screw accessible through the handle. According to the diagram on the cover, clockwise is + & counterclockwise is - .   Is this the correct screw & is ccw they way I should go lessening idle speed ?
Title: Re: Stihl MS 170 won't start hot
Post by: Cut4fun . on July 24, 2016, 11:04:27 am
Started saw cold & left it idle. Rolled saw from right side to left side. No noticeable change in idle.
You stated to turn the L screw 1/4 turn counterclockwise. I only see one screw accessible through the handle. According to the diagram on the cover, clockwise is + & counterclockwise is - .   Is this the correct screw & is ccw they way I should go lessening idle speed ?

Good on not changing while rolling over side to side.

CCW the L will lower idle. But then if needed you turn the I idle. The  one above or below in to bring rpm at idle back up if needed.  Think above the L on this carb.

Look at the 170 IPL I sent in PM here. It shows carb and L and I on it I think.  Will try and find a pic.
Title: Re: Stihl MS 170 won't start hot
Post by: Cut4fun . on July 24, 2016, 02:36:24 pm
Big silver one is the I idle.  The black ones side by side are H and L. Yours should just have the L no H.

(http://i.ebayimg.com/images/g/ptEAAOSwPhdU0p7s/s-l400.jpg)
Title: Re: Stihl MS 170 won't start hot
Post by: BHB on July 24, 2016, 03:00:29 pm
I just looked at the original carb  which is a Zama. The new carb was the same as the original  carb with the Stihl name on it (Zama also). Both carbs only have one screw. There is no L or H screw on carb however there are sealed holes that are marked L & H. I guess non adjustable factory set.
Title: Re: Stihl MS 170 won't start hot
Post by: Cut4fun . on July 25, 2016, 01:48:37 pm
I just looked at the original carb  which is a Zama. The new carb was the same as the original  carb with the Stihl name on it (Zama also). Both carbs only have one screw. There is no L or H screw on carb however there are sealed holes that are marked L & H. I guess non adjustable factory set.

 :o   Never saw that before.

I'd be buying one with L H and matching it up to yours for $12-$16 shipped.

Title: Re: Stihl MS 170 won't start hot
Post by: Al Smith on July 28, 2016, 04:49:41 am
I've never even seen a 170 .However on occasion no matter who made the saw the solid state electronic ignition systems temporaily fail from a high heat condition.
Try letting it idle for say 30 seconds before you shut it down and see if that makes a difference .
Title: Re: Stihl MS 170 won't start hot
Post by: BHB on July 28, 2016, 07:28:55 am
Will give it a try.