QuestionI have a 12.5hp Briggs and Stratton on a rider platform. I started the engine
(after changing the oil and spark) and I noticed gas coming out of the
exhaust. Also, below the carburetor, there is a small black tube coming out
of the engine. There was a gas and oil mixture dripping out. The engine
kicked over, but stalled soon after. When I disconnected the black tube, the
engine started just fine, but after about 3 seconds, a gas and oil mixture
started shooting out of the tube. There seems to be gas in the oil. I hope
my description is helpful. Anything you can suggest to help would be great.
Thank you for your time!
Wayne
AnswerHello Wayne:
This Problem is caused by Gas in the Crankcase Oil. Usually the Gas in the Crankcase Oil, Gas Spraying out of the Crankcase Breather (where the rubber tube is attached to the engine) or White Smoke (if you get the engine to run) is Caused by a Bad Diapgragm in the Fuel Pump, a Blown Head Gasket between the Cylinder and Push Tube Galley, the Crankcase Vent Stuck/Frozen/Broken or the Carburetor Flooding the Engine. 1- Clean and Soak the Carburetor. **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) and Needle Valve and 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. Install New Parts if Required.** 2- Block the Outlet Port and Pull a Vaccum on the Fuel Pump. If it Holds Vaccum, then it is Good. If Not, then the Diaphragm is Busted and the Pump Requires Replacing. If the Fuel Pump is Good, then Check the Crankcase Oil for Gas Contamination. If the Crankcase Oil is Contaminated, then Drain and Refill the Crankcase Oil with Fresh Oil. 3- **If the Mower has a Manual Gas Shut Off Valve: Check the Manual Cut Off Valve and Make Sure it is Cutting Off the Gas Flow to the Carburetor. If Not Stopping the Gas Flow, then Replace the Valve. If the Mower Does Not have a Manual Cut Off Valve: Install a Manual Cut Off Valve and Turn Off the Gas Flow when the Engine is Not in Use.** 4- If the Valve is Good or has Been Installed, then Remove the Cylinder Head. On the OHV Engines the Head gasket will Blow Between the Cylinder and the Push Tube Galley. This Allow Oil to be Sucked Into the Cylinder from the Crankcase and the Extra Oil is Just Enough to Cause the White Smoke. 5- Check the Crankcase Breather and Make Sure it is Clean and Operating Properly. If the Crankcase Breather Sticks, then Oil is Pulled from the Crankcase into the Carburetor Throat and this Causes the White Smoke. 6- I Listed the Possible Causes in the Order they Usually Occur. I have had Some People Ask me Why I do the Diagonstics in the Order I Use and it is Simply that Over the Years I have Made a List of the Equipment, the Models and the Problems they have When I Receive them for Repair. Then I Listed the Cause and Repairs Made. I Suggest you Purchase the Service Manual for this Engine. It will have All the Information you Require to Maintain and Keep this Engine Running Good for Many Years. I have Seen So Many Different Makes and Models of Equipment Over the Years, that I Use the Manuals Always for Any and All Repairs. The Basics are Not My Worry; it's the Specifications that Change. Thanks for Using All Experts.
