QuestionQUESTION: I have a Poulon Pro 20 hp lawn mower that I am fixing up. It sat for about 2 years and i finally decided to fix it up. I got a new battery, new spark plugs, and new gas line and filter. It had the old gas still in it so i drained it and put new stuff in. When I try to start it, it turns over just fine but the air intake makes a loud popping noise. And the gas doesn't seem to be getting to the carb. What is going on?
ANSWER: Hello Joey:
No Worries. From your Description it Sounds like; 1- The Carburetor Requires Soaking and Cleaning. The Cost of the Cleaning Solution I Use is $30.00us @ Gallon (I Use Gunk). The Gallon Can Comes with a Tray for Small Parts and the Carburetor Fits Nicely. Most Times a Carburetor can be Soaked and Cleaned and with the Float, Needle Valve and Other Carburetor Components being Soaked in the Cleaner with the Carburetor Body; there are No Parts to Replace on this Carburetor. If you Soak and Clean this Carburetor and the Float Needle Valve Still Does Not Stop the Gas Flow Properly, then Purchase a Needle and Seat Kit and Replace it. The Following is a Basic File I Made for Cleaning Carburetors. Any Input is Appreciated. The Most Common Cause is; The Carburetors Internal Passages are Restricted by Varnish that Gas Forms Over Time. This Varnish is in Layers. To Properly Remove this Varnish you have to Soak the Carburetor. The Following is a General Instruction File for Carburetor Cleaning. Even though the Carburetor Looks Clean, the Internal Passages May be Restricted with Varnish that Gas Causes to Build Up over Time. I Suggest you Make Sure the Gas is Free Flowing to the Carburetor Inlet Port (if the Model does Not have a Fuel Pump). If the Gas is Free Flowing to the Inlet Port, then **Remove, Disassemble and Soak the Carburetor Overnight in Carburetor Cleaner (I Use Gunk). I have Found that Most People can Use a Breakdown/IPL and Disassemble the Carburetor Enough for Proper Cleaning. You Only have to Remove the Bowl (if Applicable), Float Pin (if Applicable), Float (if Applicable), Needle Valve and Needle Valve Seat if Applicable. This is a Flat O-Ring Located in the Inlet Port the Float Needle Rests in. Use a Strong Wire with a Slight Bend to Remove the Old Seat. Sometimes a Small Pocket Screw Driver can be Use Also. The New Seat will have a Slightly Beveled Side and a Flat Side. The Flat Side goes Towards the Carburetor Body when Inserted into the Inlet Port. Spray the Seat with Spray Lubricant to make Installation Easier. The End of a Drill Bit that is Slightly Small than the Seat can be Use as an Insertion Tool. Wear Gloves or Use a Rag when Handling the Sharpened End of the Drill Bit. Remove Any Adjustment Screws that Go Into the Carburetor Body. The Welch Plugs Do Not have to be Removed. Then Soak the Carburetor Body and Parts in a 1 Gallon Can of Gunk Carburetor Cleaner Overnight. The Can has a Parts Tray Inside it for the Small Parts. Once the Carburetor and Parts are in the Cleaner, you can Replace the Lid for Safety and to Prevent Accidental Spillage. Then Blow Out the Passages with Compressed Air.*** (Do Not Use High Pressure Air for the Zama Carburetors, they have Check Valves for the Primer and these are Usually Blown Out of the Carburetor if Not Careful. Allow the Zama Carburetor to Set on a Drip Pan and Dry)***. ****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 Nearest 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 **Do 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.**** If This Carburetor has a Single Air Adjustment. Use the Section Above that Pertains to Full Throttle RPM Air Mixture Screw and then Adjust the Screw if Required to Eliminate Any Hesitation when Throttling from Idle to Full Throttle. This file was Intended to Give you the Basic Carburetor Cleaning Instructions and May Not Reflect Your Carburetor Components. If you have Questions, Please Ask. and 2- A Stuck Intake Valve. For this Repair I will Require the Make, Model and Type/Specification Number so I can Provide the Proper Instruction File for this Engine. We can have this Running like New in No Time. You have some Work to Perform so and I want to be Sure we are on the Same Page so to Speak. Send me the Model and Type or Spec Numbers Off the Engine or the Mower Model Numbers, Please. With these I can Locate the Proper Manual and Better Assist you. The Engine Model Numbers May be Stamped Into the Blower Housing (metal engine cover) Above the Spark Plug. The Mower Model Numbers are Usually Located Under the Seat on a Sticker on the Body of the Mower. Thanks.
Respectfully
John
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
---------- FOLLOW-UP ----------
QUESTION: Ok, I tinkered around on the engine, but I didn't trust myself to cleaning the carb, so I looked up the engine and found out there is a small fuel pump on it. Its a Briggs & Stratton engine and they have fuel pumps. I put a little fuel in the line leading from the pump to the carb and let the fuel seep into the pump and what do you know! It just needed to be primed and it started right up! But it still made that loud popping noise. I looked at the engine some more when it was running and I noticed only one or my exhaust pipes is blowing. So I'm guessing only one of my cylinders is firing. Is this what is happening? And if so, how do I fix it?
Thanks a lot
Joey
ANSWER: Hello Joey:
Great. You got Lucky the Carburetor wasn't Restricted by Varnish that Gas Forms Over Time. I Really Require the Model and Type Numbers Off the Engine to Assist you Properly. However, I Suggest you check the Dead Cylinder for Fire at the Plug. If No Fire, then; **To Check the Ign Coil; Remove the Spark Plug/s. Wrap a Wire Around the Threads of the Plug and Attach the Other End of the Wire to the Engine Block. Remove the Blower Housing (metal engine cover). The Wire that is Connected to the Coil/Ign Module from the Shut Off Switch needs to be Removed (unplugged) from the Coil/Ign Module. Now Check for Spark at the Plug. If Spark, then the Shut Off Switch or the Wire is Bad. If Still No Spark, then the Coil/Ign Module is Bad. If there are Safety Switches on this Unit and the Coil is Good; you Need to Check the Safety Switches for Being Bad Also.** Some of these Briggs Twin Cylinder Engines Use 1 Coil and Some Use 2 Coils. If the Plug is Firing, then; the Carburetor May be Restricted on 1 Side and Not Feeding the Dead Cylinder any Fuel. For Better Assistance, Send me the Model and Type or Spec Numbers Off the Engine, Please. With these I can Locate the Proper Manual and Better Assist you. The Model Numbers May be Stamped Into the Blower Housing (metal engine cover) Above the Spark Plug. Many horizontal shaft, overhead valve engines have these numbers stamped into the OHV rocker cover. However, on certain overhead valve powered generators, the equipment manufacturer installs a decorative chrome rocker cover OVER the Briggs cover. If your engine has a decorative cover, it may be necessary to remove it in order to locate the Model, Type, and Code. You can Also Use this Site Addy; http://www.briggsandstratton.com/maint_repair/BS_modeltypecode.pdf for Assistance in Locating the Model, Type and Code Numbers of the Engine. You can View a Breakdown/IPL of the Engine at this Site Addy; http://www.briggsandstratton.com/maint_repair/manual_and_more/doclist.aspx?categ and Enter the Model Numbers (XXXXXX) and the First 4 Type Numbers (XXXX) in the Appropriate Boxes and Click GO. Then Select Download PDF. 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. Ratings and Comments are Greatly Appreciated. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: Hey! Good news! I got it running on both cylinders. I took the valve cover off and noticed that some rods were not connected so i put them back on and hallelujah she runs great! But I was having trouble with it blowing fuses until I noticed a bare wire. Got that fixed and then was driving her around. When I turned her off, she was smoking, but I've run her a couple more times and she isn't smoking as much. Don't know if that is just the engine burning off residue from sitting for so long or what. But there is one thing left I'm not sure about. When I throttle down, a flame shoots out the pipe that wasn't working before. It also shoots out every once in a while when its idling, but its a lot smaller of a flame than when I throttle down. I hope its just excess gas igniting in the pipe and not something serious. Also, I think gas is leaking into my oil but I'm not sure. Its smells faintly of gas. But it isn't watery.
~Joey
AnswerHi Again Joey:
Now We Know the Reason the Mower was Parked for a Few Years. Someone May have thought the Engines Crankshaft was Bent. The Way the Engine Act when it Tries to Start with the Valve Clearances too Wide or the Push Tubes Not Resting on the Rocker Arms Properly cause the Engine to Turn 3/4 Turn and then Slow/Stop and Drag for 1/4 Turn. A Lot of People were Associating this with a Bent Crankshaft and Did Not want to Spend the Money to Replace the Crankshaft. I have had Several People Purchase Short Blocks and then Find the Problem to be the Valve Clearances were too Wide or the Push Tubes had Jumped Off the Rocker Arms. Here is the Valve Clearance Setting Instruction File for Briggs Engines. The Clearances are Correct for Most Briggs Engines and a Few Tecumseh Engines. The Following is a Basic File I made for Setting the Valve Clearances. Any Input is Appreciated. **I Do Not Use the Setting Called for by the OEMs. I have Found that the Following Works Best. Remove the Valve Cover (on the Dead Cylinder for Twin Cylinder Engines). Set the Cylinder you are Setting the Valves on to Top Dead Center on the Compression Stroke When Setting the Valve Clearance. Now Loosen the Valve Adjuster Locks and Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .007in - .009in. I have had Better Performance Out of the Mowers and Less Burnt Valves Using these Settings. Be Sure the Piston is at TDC on the Compression Stroke.** On Some Engines you can Us a Straightened Coat Hanger and Feel the Piston. Be Careful and Dont Jam the Wire in the Cylinder. Usually the Piston will Push the Wire Out of the Spark Plug Hole with No Problems. 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. Ratings and Comments are Greatly Appreciated. Thanks.
Respectfully
John
