Small Engines (Lawn Mowers, etc.): 18HP B&S Engine, carburetor body, bolt torque

Question
Hi John,
I removed both heads and the valves appear to be moving properly without sticking. The valve seats and valves appear to be in good shape. No ridge appears in cylinder bores. However the combustion chambers are very black and at the bottom right corners there appears to exhaust blowby between the head and block. Also the bolts (3-4) in this area appear to have blank exhaust and somewhat wet in some cases. The gaskets appear to be fine. It appears that maybe the bolts had loosened up in these areas and this is why the compression is low (75/80 lbs).
It appears that the engine is running very rich. I had set the idle speed mixture screw to 1 1/2 turns. When the engine orginally ran, I normally choked it and then pushed in back in almost immediately after it started. Also if you had looked down the carb, you could see wet gas in the intake manifold.
Could the loose head bolts and rich gas be the problem. If so, please advise recommended head bolt torque and how to lean the carb out.  Should I clean thr combustion chamber with carb cleaner? Also any other suggestions would be greatly appreciated. Thanks again with your patience with me.  

Kevin

Answer
Hello Again Kevin:

1 Loose Bolt can Cause Some Compression Loss. 2 Loose Bolts Will Definetly Cause Compression Loss. Set the Air Mixture Screw as Indicated in the Instructions that Follow. I have a File that I Copy and Paste from so Set the Air Mixture Screw as if the Carburetor has 2 Air Mixture Screws. All the Carburetor Adjustments are the Same for Lawn Mower and Trimmers. There are Several Location for the Air Mixture Screws. The Idle Air Mixture Screws are Usually Located at the Top of the Carburetor Bowl and the Top of the Carburetor Body. If the Main Air and Idle Air Mixture Screws are Side by Side on the Side of the Carburetor, then the Idle Air is the Farthest from the Engine. The Main Jet Air Mixture Screw is Located in the Bottom of the Carburetor Bowl or Beside the Idle Air Screw on the Side of the Carburetor Body. Some of the Older Model Carburetors have the Main Jet Mixture Screw Straight in from the Top of the Carburetor Body (this is Rare anymore). If you have Cleaned the Carburetor (Disassembled and Soaked Overnight in Carburetor Cleaner (I Use Gunk). Then Blow Out the Passages with Compressed Air and Install a New Kit if Required. Now Setting the Air Mixture Screws:  ****Turn the Idle Air and Main Air Mixture Screws In Until SNUG **Don Not Jam** Then Reverse Both Screws 1 1/2 Turns. Holding the Throttle Full Open, Start the Engine. Turn the Main Air Mixture Screw Clockwise Until Proper Revs are Obtained. Occasionally you May have to Turn this Counter Clockwise to Achieve the Proper Revs. Now Allow the Engine to Idle. Set the Engine Idle Screw (Not Idle Air) so the Engine will Stay Running if Required. Now Set the Idle Air Mixture Screw so there is No Hesitation when Throttling from Idle to Full Throttle. Reset the Engine Idle if Required.****  The Head Bolts are Torqued to 40 to 45 Ft Pounds. If you have Access to Compressed Air and can Blow Out the Cylinder After Cleaning the Carbon, then Do So and Blow Out the Cylinder Really Good After Cleaning the Piston Top. If No Compressed Air is Accessible, then Do Not Clean the Carbon Off the Piston Top. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. 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 you Question at or Just After 9pm EST (US). My New Day Starts then. Thanks.

Respectfully

John