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Stihl backpack won't start

Zach76

LawnSite Member
Location
Omaha, NE
Alright guys, Today was only the second day I have even tried to start my new Stihl BR420. Last time, I tried for like 20 minutes, then it started and ran like a champ all day. Today, I spent 20 minutes at my first property before I broke out the push broom. At my second property (mom and dad's house) I spent about 1/2 an hour trying to get it to start before the push broom came out. Finally I just decided that it was a push broom kind of day, but I can't figure out what's wrong. I've tried replacing the spark plug, removing the air filter and cranking it, choke, no choke, full throttle, minimal throttle, and everything else I can think of. Any ideas before I take it back to the dealer?
 

lawnman_scott

LawnSite Fanatic
Location
st pete, FL
Did you remove the spark arrester? The useless screen over the exaust discharge on the muffler. It shouldnt be a problem so soon, but other than that i would take it back.
 
OP
Z

Zach76

LawnSite Member
Location
Omaha, NE
I pulled off the spark arrester. i know I'm getting fuel, but spark is something I question. That's why I tried the new spark plug. I even tried putting my hand on the spark plug boot while I tried to crank it to see if it would shock me (I know that wasn't the smartest idea) and it didn't. I don't know a whole lot about small engines, so I'll probably just end up taking it to the dealer, I just hoped to be able to fix it myself. Thanks for the responses guys.
 

Richard Martin

LawnSite Fanatic
Location
Greenville, NC
Most likely it ain't broke.

Stihl backpack blowers can be a bear to start if you're not used to them. Do this: No throttle, full choke, 2 pulls, back the choke off to halfway between full choke and no choke and pull it again a few times. It should start right up. If it still won't start then check the plug to see if it's wet fouled from your previous attempts to start the blower.
 
The day you take it to the dealer it'll start. These flood so easily, and once they do they're pretty well done for the day.
I've taken the plug out, turned the blower upside down for a couple of hours to let it dry out. Then it would start if I used the sequence Richard described.
I use only synthetic 2-cycle oil in mine.

Dave
 

grass_cuttin_fool

LawnSite Gold Member
Location
Virginia
I agree they can flood easy, but from what you posted it sounds like you arent getting any spark. And have you tried the switch to make sure its in the on position???? Im quilty of that crank and crank and look at switch and say ooooops
 

bobbygedd

LawnSite Fanatic
Location
NJ
it does this to me all the time. put it on choke, pull 2-3 times. take choke off, hold throttle trigger half way, pull start. don't keep pulling if this don't work, they do flood easily. if the half throttle don't work after 2-3 pulls, put it on full throttle(using the lever provided) and try it. this is how i start it all the time. get a redmax
 

KenH

LawnSite Bronze Member
Location
CT
You wont get shocked if you put your hand on top of the boot (unless the boot is worn). Take out the plug, hook it to the boot and pull the cord. See if you can see the arc at the tip.
 
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