Small Engines (Lawn Mowers, etc.): Idle screws, 2 extremes, load speed

Question
Tecumseh OH 195 XA Spec#71228
Otside the carburetor there is a top and a bottom screw both with springs.I am guessing this is a high and low setting for what?
What is the one on top for...and how should i adjust it?
Also the one on the bottom ...I need the same info on that too.
I also have the main Idle screw.Thankyou so much.
James

Answer
hi

the very top screw  is the idle speed screw   clockwise  adjustment will raise revs and visa versa

the second screw  is the idle mixture screw    

turn this screw in untill it seats lightly and then back it out 1.5 turns as a start point
start engine  and adjust  so that engine idles reliably  and accelerates smoothly
1/8 turn at a time  only  and note what engine does

the bottom screw on the bowl is the main jet adjustable scew

adjust this while engine is running at top no load speed

turn it out until engine faulters  then turn it in until it faulters  the set it  between those 2 settings  when rich engine runs heavy  , when lean it runs too fast and hot
we need it  in the middle of those 2 extremes



cheers paul  

hope it helps