Walbro Adjustment epa

[Mack90]

https://www.walbro.com/tech-tips/proper-idle-and-high-speed-needle-adjustments/
I was trying to adjust the carb on a newer husky 440 and could not get it tuned right yesterday. Today I read the low can be as much as 4 turns out . Any tips for carbs with these crazy carbs

 

[HarleyT]

Got any pics?

 

[HarleyT]

This one is off of Partstree.

 

[Backstage]

Check basics first.

GOOD fuel? Warmed up? GOOD fuel? clean? GOOD FUEL? spark plug? Good fuel? Compression and other mechanicals good? Good fuel?

Then go ahead, pull the carb, and mess with the limiter caps. Check vacuum on the lines and so forth.

 

[Mack90]

Chainsaw has fresh fuel ethynol-free 50:1 mix. I haven’t pulled the sparkplug on it, but runs highend fine with 1.25 turns out. When I went to fine-tune low end… I slowly turned in screw and my jaw dropped after 3 turns… factory setting. I can’t get it to idle for long now without turning up idle adjust. There are no limiters.

 

[Mack90]

Thus saw only has about an hour on it.

 

[Mack90]

here are pics

 

[mbrick]

Get the specialty splined screwdriver and tune it like any other carb.

It may have screw limiters that require removal to get to the right settings or it may not have them or it could fall within the limiter adjustment range.

 

[Tomos770]

I have 450 mk2 myself...

Regarding the look of its muffler screen......

Are you sure that you are mixing your fuel @50:1? Semi-syn or synthetic oil?

 

[Mack90]

Yes, husky oil 50:1

 

[Mack90]

I just cut half a cord with it. Will keep trying to get it to idle ok. Thanks for the advice.

 

[Mack90]

Update - I was able to get this saw tuned perfectly. It took almost 4 turns out on low side. The whole time I had the low side too lean with the idle set to high. I guess with the idle screw too high the high jet was controlling the idle. A big part of the confusion was the chain turned at idle. I got a tachometer and realized the idle speed was not the problem, but the oiler was causing the chain to spin. Fixed oiler and all is good!