# Br 420 carb help



## Rich86 (Jan 9, 2022)

Hi
I have a br 420 That i just rebuilt with all new oem everything including new fuel tank hoses etc new oem coil and new oem carb. The engine was air and vac tested before reassembly. The new carb would not fire until I removed the red caps. I could only get the blower to run at 1 3/4 high 2 3/4 on the low side at first gas was coming out of the muffler then once I played with a little more it stopped coming out. I am wondering if these adjustments are acceptable or it will seize from it being out of adjustment. Any help will be appreciated thanks


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## cscltd (Jan 12, 2022)

That carb usually is 1 & 1 on settings from what I remember. 
there is two different modules for it but not sure if it matters as only 1 crank and flywheel. 
somethings not right, try old module and or old carb?


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## Rich86 (Jan 14, 2022)

cscltd said:


> That carb usually is 1 & 1 on settings from what I remember.
> there is two different modules for it but not sure if it matters as only 1 crank and flywheel.
> somethings not right, try old module and or old carb?


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## Rich86 (Jan 14, 2022)

My old coil had no spark and the the old carb would not fire at 1 turn out on high and 1 on low


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## cscltd (Jan 14, 2022)

Might have a air leak, have to do a pressure vac test on it


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## ray benson (Jan 15, 2022)

Rich86 said:


> Hi
> I have a br 420 That i just rebuilt with all new oem everything including new fuel tank hoses etc new oem coil and new oem carb. The engine was air and vac tested before reassembly. The new carb would not fire until I removed the red caps. I could only get the blower to run at 1 3/4 high 2 3/4 on the low side at first gas was coming out of the muffler then once I played with a little more it stopped coming out. I am wondering if these adjustments are acceptable or it will seize from it being out of adjustment. Any help will be appreciated thanks


BR420 carb settings


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## Casawfan (Jan 15, 2022)

As mentioned earlier 1H and 1L should get you started and is a good baseline fine adjust from there. Of all the Stihl stuff I've owned by far the most frustrating as a BR420. Mine always started hard after sitting I suspect because the carb was much higher than the tank fuel would drain back down even after carb rebuilding and replacement thereafer. 

Hope you get it figured out.


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## Rich86 (Jan 15, 2022)

cscltd said:


> Might have a air leak, have to do a pressure vac test on it





ray benson said:


> BR420 carb settings


Thank you


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## Rich86 (Jan 15, 2022)

Casawfan said:


> As mentioned earlier 1H and 1L should get you started and is a good baseline fine adjust from there. Of all the Stihl stuff I've owned by far the most frustrating as a BR420. Mine always started hard after sitting I suspect because the carb was much higher than the tank fuel would drain back down even after carb rebuilding and replacement thereafer.
> 
> Hope you get it figured out.


Thank you


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