Small Engines (Lawn Mowers, etc.): Adjusting Fuel Mixture, phillips screw driver, carburetor adjustment

Question
I just purchased a used Honda HRT216SDA Lawnmower which has been difficult to start.  I noticed the spark plug was fouled so I cleaned it and re-gapped it.  However, I suspect that the carburetor is mixing the fuel too rich (5000' elevation) and so I want to adjust it - the manual has no instructions and behind the air filter I noticed a red-colored screw that is virtually impossible to reach (except with an 18" long Phillips screw-driver).  It appears this would be the only adjustment I can make - the question I have is which way do I turn it to make a leaner fuel mixture (clockwise or counter-clockwise) and how much should I try adjusting it 1 or 2 turns or more?

Thanks.

Answer
Hello Jim:

The Red Colored Screw is Actually a Limiter cap for the Air Mixture Adjustment Screw. You Need to Turn the Adjustment Screw Clockwise to Lean the Fuel. Have you Checked the Exhaust Port for Blockage? Remove the Muffler and Inspect the Exhaust Port for Carbon Blocking the Exhaust Port. Check the Muffler and Spark Arrestor Screen (in the muffler) for Carbon Blockage Also. If the Exhaust Port or Muffler is Clogged, you will have the Problem you Described. I Suggest you Check the Exhaust Port and Muffler First. Then Do the Carburetor Adjustment if Required. You may have to Break the Limiter Cap to Get Enough Turn on the Adjuster Screw. The Limiter Allows for 1/4 to 1/2 Turn Only. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Thanks.

Respectfully

John