Small Engines (Lawn Mowers, etc.): 790r Carb Settings, set screw, carb settings

Question
Hi Michael:

Recently someone asked you about the carb setting for a 790r.  I will presume this is for a Rayobi 790r and if it is, I apprecaite your expertise as I have been looking for someone to ask the same question of.  

However I am confused and hopefully you can help me out.

Before I ask my question I will remind you of the question and answer you recently gave.

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Original Question:


When the engine is running with throttle open, it runs rough and doesn't reach high speed. When I open throttle fast the engine can die. It seems starved for gas. H & L screws on carb. Turning H screw out seems to improve, but not enough. Idle is ok. Any suggestions on proper screw setting?

Answer
Hi Russ,

The initial setting for the jets are: High speed = 1&1/2 turns out. Low speed = 3/4 turn out. If the high speed jet is much further out, try closing it a bit to give higher rpms. If the jets don't help then the carb may need rebuilding or cleaning. The spark arrester screen or muffler may be clogged also.

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I hope I can ask my question in an understandable manner:

I have a used Rayobi 790r that a friend gave me. It appears to have been manafactured in 1995. I have no service manual or repair manual.

It runs very rough.  I need to, and have tried to, adjust the carb. I took off the carb cover to get to the set screws as there is not an opening in the carb cover to make the adjustment.

Just behind the choke lever there are two set screws. These have to be the "H" and "L" set screws you refered to.  However, I did not know which set screw is "H" and which one is "L".

Okay I took the  long way around to ask you which set scrwe is "L" and which set screw is "L".

I am sure this will solve my problem.




Thanks...

Grady


Answer
Hi Grady,

Clean the area well.   They usually are always marked.  If not, then close each, while counting the amount they are opened now.  They should be close to the correct setting.  The one that is open the most is probably the high speed mixture screw.  Then reset them to the recommended setting and adjust from there.

Good luck.
Michael