QuestionQUESTION: This is the discontinued propane fueled unit. We have 187 hours on it and it has been getting very difficult to start and now it won't. The fuel delivery seems to work as it should and there is spark. I checked the valve clearance, it was just about .002 over on each which I adjusted. It cranks ok and occasionally backfires through the carb. Any ideas or suggestions?
Thanks, Jerry
ANSWER: Hello Jerry:
From your Description it Sounds like the Head Gasket May have Blown, the Carburetor is Not Supplying the Proper Amount of Fuel or a Valve is Burnt and Requires Reseating. Will the Engine Try to Start if you Use a Small Amount of Starter Fluid while Starting the Engine? If Yes, then Check the Pressure Regulator. Are you Sure the Engine was at TDC on the Compression Stroke when you Adjusted the Valves? If Yes, then Loosen the Exhaust Valve to Approximately .015in and Check the Engine Compression. If the Compression is 90PSI or Lower, then there is a Problem with the Rings and or Cylinder. Remove the Valves and Reseat them.
Good Luck
Respectfully
John
---Follow up---
QUESTION: Hi John,
Thanks for the quick answer. I had tried starter fluid with no luck. I re-checked the valve clearance again at TDC and then loosened the exhaust and got 60 psi on the first stroke and a max of 80 psi. Just before I wrote to you, I had started the engine with much difficulty and it ran about 10 seconds and then sputtered quite a bit and died and will not start again. It has been sputtering and backfiring a lot in getting it started for quite a while. Sounds like I need to pull the head a take a look.
Thanks, Jerry
ANSWER: Hello Again Jerry:
You are Correct. You Need to Remove the Cylinder Head and Inspect the Piston, Cylinder Walls and the Cylinder Head. Be Sure to Remove the Valves from the Head and Check for Burnt Valve Face/Seat on the Valve and the Valve Seat in the Head. Make Sure the Valve Seats are Not Loose in the Head. Once we Locate the Cause for Low Compression, then you can make the Repair and have the Unit Running Proper Again. 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
---Follow up---
QUESTION: Hi John,
An update on this problem. I have it back together after a complete tear down, was waiting for gaskets. The rings look fine, the bore still has honing cross hatch marks and looks good. The combustion chamber was quite carboned up, it is clean now. I was under the impression that a propane fueled unit would stay much cleaner than this did. The valves and springs looked ok but did a light lap with
fine compound and checked with Prussian blue. Good seal all around. The coil primary and secondary are to specs according to my Fluke 87. Bottom line, it still won't run. Bucks and backfires through the carb is about it. I am wondering about the automatic decompression mechanism. I looked at it but didn't understand how it functions. Do you think it may be the problem, or what have I missed? How could I check for proper propane flow?
Thanks, Jerry
AnswerHi Again Jerry:
Did you Check the Flywheel Key During Any of this Repair? Usually the Problem is Reverse of the 1 you Described if the Compression Release was the Cause Unless the Spring on the Compression Release is Broken. I have 1 of these Engine in the Shop and I will Try Today to Duplicate the Problem you are having. Usually the Carburetor, Pressure Regulator, Head Gasket, Valve Clearances, Burnt Valve or a Damaged Flywheel Key are Causes for the Problem you Described. The Following is the Instruction File I Made for Removing the Flywheel from Most Mower Engines. It is the Basics and if you have a Question, Please Ask. Any Input to Make this File Better is Appreciated. ***Disconnect the Coil Wire from the Spark Plug. Remove the Blower Housing (metal engine cover). Remove the Coil. Remove the Flywheel Nut or Starter Cup (Depends on the Model). Now Attach a Steering Wheel Puller to the Flywheel Using the Threaded Holes in the Flywheel. Tighten the Puller. Now Hit the Puller with a Hammer. Repeat this Procedure Until the Flywheel Pops Up or can be Lifted Off the Crankshaft. On Some Models you Can Not Use a Puller and Must Use a Pry Bar and a Pipe Cap that is Slightly Larger than the Crankshaft. Place the Pipe Cap Over the Crankshaft to Protect it. Place the Pry Bar Under the Thick Section of the Flywheel and Pull Up Against the Flywheel. **BE CAREFUL DO NOT PUT A HOLE IN THE BLOCK UNDER THE FLYWHEEL** Now Hit the Pipe Cap that is on the Crankshaft (covered with the Pipe Cap). Repeat the Procedure Until the Flywheel can be Lifted Off the Crankshaft. *** Be Sure you have the Flywheel Torqued to the Proper Torque (I require the Model and Spec/Type Numbers Off the Engine to Provide the Proper Torque) and Set the Coil Gap to .020in.. Is the Regulator Operating Correctly? If the Gas Pressure is Low you will have this Problem. 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. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
