Tune Carby for small two cycle engine in brushcutter

Reply

  #1  
Old 01-27-08, 10:15 PM
ozriverboy's Avatar
Member
Thread Starter
Join Date: Jan 2008
Posts: 1
Tune Carby for small two cycle engine in brushcutter

I have a 30cc brushcutter and had to replace the carby with a similar carby which works rather well except I need to tune it. I notice that there are two adjustment screws for the carby, one marked 'H' and the other 'L' which I take to mean 'high revs' and 'low revs' respectively. What exactly do I do to tune the carby so that the engine runs smoothly and efficiently with respect to the two adjustables and the idler adjuster.
Regards to all.
 
Sponsored Links
  #2  
Old 01-28-08, 12:56 AM
repair_guy's Avatar
New Member
Join Date: Apr 2004
Location: Marion,Al.
Posts: 539
Yes your right in thinking that the "H" is for high and the "L" is for low rev's.and the other screw is for idle.Take the screws with "H" and "L" on them and turn them all the way in,CW.DON'T TIGHTEN just bottom out.Then turn both screws out CCW 1-1/2 turns.Crank the engine an let it warm up.(2 or 3 min.)Then while hands off the trigger fine-tune the screw that says "L".Then with trigger mashed fine-tune the screw that says "H".If it's ideling too fast or slow then adjust the idle screw.in=faster.out=slower.TURN SCREWS SLOWLY.
 
  #3  
Old 01-28-08, 09:40 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 16,575
Be careful when adjusting them so that you don't get it running too lean. If you adjust the high speed mixture screw to the point where the engine runs the fastest and smoothest, it will ruin the engine, because it is too lean at that point. You'll want to find that point, and then open the screw a little more until the engine gets a little flutter sound at full throttle. Adjust the low speed mixture screw to the best idle attainable and just rich enough that there is a nice transition from idle to full throttle, no stumble in between.
 
Reply


Thread Tools
Search this Thread
Display Modes
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 01:42 AM.