Sthil ms170 choke lever positions

[napalm1337]

Hi,

I'm a new member and here's my first post:

I've recently acquired my father's old ms170 chainsaw in good condition, however there's an issue with the choke lever and the contact spring behind it. The spring isn't putting any pressure on the lever mechanism.

Can anyone provide a picture or any information about the various choke settings? Particularly what the choke should look like in the hot start position with the air box off? - should this be 90% closed? Or 50% assuming cold start choke is 99% closed.

I really hope this makes sense. Between the off position and the and cold start position there's no tension on the lever to depict where it should rest for run position and hot start position.

Any help or advise would be amazing.

Thanks

 

[epo]

For the run and hot start positions the choke plate should be fully open.

 

[coffeebrk]

Take a look at the left side of the choke/control rod. Where it snaps into the saw body is everything ok?
Sometimes where the rod is secured part of it can been broken off

 

[napalm1337]

For the run and hot start positions the choke plate should be fully open.

Hi, thank you for the response! If both run and hot start are wide open are you able to explain the difference between each position

 

[napalm1337]

Take a look at the left side of the choke/control rod. Where it snaps into the saw body is everything ok?
Sometimes where the rod is secured part of it can been broken off

Hi,

The choke bar is still seated on both sides with no damage. Looks like I need to bend the contact spring back into the correct position, it's just trying to figure out what position that is, so that the lever engages for hot start

 

[epo]

Hi, thank you for the response! If both run and hot start are wide open are you able to explain the difference between each position

These positions differ in how much the throttle plate (the one closer to the cylinder) is open. In the hot start position, this plate should be slightly open (let's say about 25%). In the run position, it should be almost completely closed when you don't press the throttle trigger/lockout.
The hot start position makes it easier to start the engine.

 

[napalm1337]

These positions differ in how much the throttle plate (the one closer to the cylinder) is open. In the hot start position, this plate should be slightly open (let's say about 25%). In the run position, it should be almost completely closed when you don't press the throttle trigger/lockout.
The hot start position makes it easier to start the engine.

Amazing! Thank you. Armed with this much need information il have another look it again. Honestly you've been amazing help, your time is very much appreciated

 

[napalm1337]

These positions differ in how much the throttle plate (the one closer to the cylinder) is open. In the hot start position, this plate should be slightly open (let's say about 25%). In the run position, it should be almost completely closed when you don't press the throttle trigger/lockout.
The hot start position makes it easier to start the engine.

Hi, please see photo.



Green arrow: stop position
Blue arrows: run position
Red arrows: cold start position

I don't see anywhere on the choke side or the throttle side of the bar to catch the throttle lever open slightly or the choke fully closed.

Honestly I feel like I'm have a super special moment here

 

[epo]

Hi, please see photo.

Green arrow: stop position
Blue arrows: run position
Red arrows: cold start position

I don't see anywhere on the choke side or the throttle side of the bar to catch the throttle lever open slightly or the choke fully closed.

The warm and cold start positions should not differ when it comes to opening the throttle plate. The difference should be in the position of the choke plate.
Or to put it another way if you switch the lever from the lowest position to the higher position the choke plate should open, and nothing should change on the right side of the carb.

 

[coffeebrk]

Are you depressing the throttle when setting (moving) the control lever?

 

[napalm1337]

Are you depressing the throttle when setting (moving) the control lever?

Hi, yeah for both cold and hot start

 

[epo]

Hi, yeah for both cold and hot start

Can you explain what you have a problem with now, because it doesn't look too bad in the picture?

 

[napalm1337]

Hi,

The issue is with finding the hot start position on the choke lever. In the picture above I've show 3 locations the choke lever engages/rests, but there should be a 4th position.

 

[napalm1337]

Can you explain what you have a problem with now, because it doesn't look too bad in the picture?

Moving the choke to the off position (click) down to run/idle (click) then the lever floats all the way down until you pull the throttle and engage cold full choke (click)

 

[epo]

Moving the choke to the off position (click) down to run/idle (click) then the lever floats all the way down until you pull the throttle and engage cold full choke (click)

What happens when you try to raise the lever from the full choke position to the top without pressing on the throttle trigger?

 

[coffeebrk]

Starting position full choke

 

[coffeebrk]

After catching lever up one

 

[napalm1337]

What happens when you try to raise the lever from the full choke position to the top without pressing on the throttle trigger?

It's stopped by a tab on the righthand side, it locks the throttle on

 

[napalm1337]

After catching lever up oneView attachment 1180560

This is where my issue is! The spring isn't making contact over this point, maybe a 5mm gap. The spring must be deformed from it's original shape

 

[coffeebrk]

Blip throttle