Husqvarna 257 start up question

[Keithandstef]

So this old 257 I have had an interesting start up habit (I think). If it’s dead cold and hasn’t been used in a couple weeks, I will choke it and pull until it “pops” then I push in the choke and pull and when it fires up it runs at a pretty high speed until I pull the throttle and then it’ll drop to idle after that.

if it’s warm or has been started in the last few days, as best I can tell it won’t do the high speed start up and just cranks to an idle speed.

Guess I should be happy it turns over so easily after sitting awhile but I am curious about the circuitry making it do the high idle. Is it only if it barely catches on choke that it will do that when next cranked?

 

[Derf]

The 2-series would be set to high idle when you pull out and push back in the choke lever. Once you blip the throttle it goes to regular run mode.

 

[Wood Doctor]

Derf hit the answer on the nose. 'Nuff said. Ran mine today for an hour and just sharpened the chain. It's a good saw and was a best buy from this site four years ago. All I gave it was a clean-up and a tune-up.

 

[Keithandstef]

Ya I get the high idle when it’s a very cold saw, like hasn’t been run in a week. It catches on choke and then I push it back in and then pull the cord again. When it catches then, it goes to high idle. These last few days since I’ve run it a bit it hasn’t been doing that even in that same sequence. It just goes to idle speed. Kinda weird but whatever. It starts easy.

 

[huskihl]

Ya I get the high idle when it’s a very cold saw, like hasn’t been run in a week. It catches on choke and then I push it back in and then pull the cord again. When it catches then, it goes to high idle. These last few days since I’ve run it a bit it hasn’t been doing that even in that same sequence. It just goes to idle speed. Kinda weird but whatever. It starts easy.

It’s a mechanical linkage independent of the temperature. When you put the choke on, it closes the choke and sets the high idle. When you push the choke in it opens the choke and leaves the throttle butterfly cracked a little bit in the high idle position until you pull the trigger.

 

[Keithandstef]

Could it have anything to do with how the T screw is set? Whatever that one is called. The non high and low screw. I did mess with that the other day but just enough to keep the chain from turning at the proper low rpm. I’m very confident the low and high screws are set just right.

 

[Wood Doctor]

"Could it have anything to do with how the T screw is set?"
I doubt it. Start by cleaning the air filter. That will shut it down faster than anything else. The other symptoms that you mention I have never observed. Derf called it in post #2. Did you read what he said? If you pull the start out, it remains choked until you press it back in. Press it back in and high idle stays on. If you want high idle, pull the start out and press it back in. Nothing could be simpler than that. Got it?

 

[Keithandstef]

Yes I read it and understand what you guys are saying. But it doesn’t always behave that way.

 

[Keithandstef]

Mystery solved. The linkage input above helped a lot. It turns out the two bolts holding the air filter intake to the saw body had come slight loose. The right side one more than the left. This is important because the choke linkage is on the right side too and the little bit of play due to the loose boltd was keeping that very slight post choke high idle hold from “sticking”. It was essentially just making the choke work like a choke and nothing more. Bolts tightened and you can see the linkage working correctly just flicking the choke on and off and then blipping the trigger even when the saw is off. Thanks guys as always for the help.