Any Stihl tech's out there ? Need help with a Stihl

rjh1

Full Member
Joined
Jan 9, 2007
Messages
133
Likes
1
Points
18
Location
Ohio
#1
Stihl BR550 back pack blower 4 mix .. whats been done so far new fuel lines - primer bulb - fuel filter - carb - coil .. adjusted valves to 4 thou new spark plug gaped at 20 thou .. It starts runs .. but has a miss when running ??? it throttles up i adjusted carb .. but it idles with a miss ?? this is the first 4 mix so not sure of the ins and out of this type of unit .. need assistance with what is the miss all about ?? Thanks !
 

rjh1

Full Member
Joined
Jan 9, 2007
Messages
133
Likes
1
Points
18
Location
Ohio
#2
Well i guess there are no stihl techs out there :eek: ? ? so i'll let this die where it is .. thanks for the non help ...:rolleyes:
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,076
Likes
62
Points
48
#3
I did read a bit about that "4 mix" engine after you started this thread. It is rather a bastard design, in my opinion; a "throw-away" with more complexity than worth trying to fix. Stihl tries to put a positive "spin" on it, but it is a design forced by tightening emissions/economy/noise regulations. I didn't think my opinion was the kind of help you would appreciate, so I kept quiet...