Unable to start MS170 so advice needed for me to rule things out

[ipbr21054]

What is the purpose of this item.
It sits between engine block & coil.

Surely without it the coil will still operate as the bolts mount flush with the coils metal part so shorting out isnt an issue.

So assume for vibration etc ?

Just trying to look at every possibility now.

 

[Burnerman]

This is a heat insulating spacer, and won't stop the coil working.
As you've found, the key is part of the flywheel on these engines and yours looks fine.
I have to conclude you have a dud carburettor here.
John

 

[ipbr21054]

Hmmm
On ebay & Amazon market is flooded with chinese copies even well known garden suppliers are selling chinese copies.
Dont want another but what can i do as original is £££££££££

 

[ipbr21054]

The photo i supplied was taken from internet to show there isnt a separate woodruft key & is part of the flywheel as shown.

I then took mine apart again & see photo of what i found.

So i would say as i am getting a spark it isnt at the correct time hence why im having these issues.
If key was 100% present the spark can only be made at around TDC and mine isnt so i dont think it is sparking on the correct stoke / time.

Majority of mine is missing & i found it stuck in crank.

What do you think now ?

My luck would be also something else ha ha

 

[Burnerman]

It looks like the flywheel key has sheared (from here, anyway) so a new flywheel is required.
Is the crankshaft key slot damaged at all?
John

 

[ipbr21054]

Crank is fine so i assume spark doesnt fire at correct time, another flywheel has now been ordered

 

[Burnerman]

Just a word of wisdom when fitting the new flywheel........grip the flywheel as you tighten the nut - avoid the temptation to hold the other end of the crankshaft as it will twist.
John

 

[ipbr21054]

Ok thanks.
Don’t want to break it off.

 

[ipbr21054]

Flywheel arrived today.
Whilst waiting for it to arrive i had a carb which was new but hadnt fitted or used BUT it did have the L & H jets.
So adapted the saw to allow full access to these screws & also the tickover just below.

Fitted the flywheel & the result is in the video clip.

Just need to set up carb correctly but at present L 1 turn out from seated, H 2 1/4 turn out from seated.

Result



MS170 VIDEO CLIP

 

[Burnerman]

Result indeed!
Pleased you've got it sorted.
John

 

[ipbr21054]

I started the saw up yesterday & there was white smoke. It did clear after a while but occasionally when I blipped the throttle I seen a bit more. This seemed to be by exhaust / chain.
I fitted a new exhaust but it’s not that.

This afternoon I started it up & let it get warm then adjusted the L screw by finding a happy medium between where the rebs start to drop off. It also did it then.

My mix was 1 litre of fuel in the mixing bottle & then I added stihl 2 stroke oil up to the 50:1 line

I’m sure I’ve been here before a year or two ago & then didn’t put as much oil in but the manual does say 50:1
Last thing I want is to run it lean & damage the piston / bore.

New air filter.
New plug.

 

[ipbr21054]

Just to advise how I did the L screw adjustment.
L screw all the way in then 1 full turn out.
Warm saw for a minute or two.
Turn L screw anticlockwise until engine started to slow up.
Then L screw clockwise until engine started to slow up.
Then got it kind of in the middle of these two positions.

H screw is 2 full turns out from seated position & left it there.

Tickover is at a gentle speed & bar / chain isn’t spinning.

When I then grab the throttle lever there is no lag & its reaction to respond is fine.
No bogging etc.

Leave for half an hour & saw starts on second pull.

It’s then happy to dance of the floor whilst ticking over.

The carb I’m sure was from a 017 which has the L & H screws.

This was used to replace the carb with no jets & just the tickover screw.

 

[Burnerman]

Yes, that's exactly right......just see what power you have when in the depths of a heavy log!
Ignore any smoke - it will be residue lubricant and if any more occurs it's likely to be blue.
I'm using Stihl mixed two stroke fuel (50:1) all of the time now - expensive but worth it......these machines really don't like E10, too much ethanol which upsets the carb diaphragms.
P.S Don't let your saw dance on concrete - you can wear the aluminium away!
Regards
John