Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Carburetor is a none adjustable model. Only adjustment is idle speed. The needle valve and float, control the fuel flow into the bowl.
With this engine, you may have a valve sticking or that needs to have some clearance. Problem with that, is the valves have to be removed from the block and ground off to add clearance.
You can check valve clearance by removing the valve cover, that the vent hose comes off of, and see if valves are too tight. .006 will be good. Zero causes problems.
Engine breather page 87, is where you remove and check valve stem and springs for clearance between valve stem and lifter.
You can check them, but not adjustment them without disassembly!
#172 is the cover shown for your engine, the cover and baffle have to be removed, and you should them see the valves and springs and lifters
Take it off, go deeper!
Thats it. The valve stems and the lifters, You want to measure the gap between stem and lifter. Use feeler gage and see if you can slip at least .004 between the two parts, you will have to turn engine until the valves are closed,
Accuracy is not that close. You can turn engine and hold gage against the two parts, if there is clearance ,the gage will slip through when valve reaches its lowest point. As long as it has clearance it should work, and not cause the misfire. Zero is when it causes the problem/
Here is basic valve setup. Your lifter is not a rocker, but a rod pushed by the camshaft, but it should give you idea where you check the gap.
Here is Utube video.
You can still have valve problem, valves may not be seating, and would need to be reseated.
I will be here tomorrow , most of the day. Let me know what you find with clearance.
There will be a link in your Email to get back.
Only time there would be a gap is when the valves are all the way down. When you were turning engine, did you have spark plug removed? If not you were feeling the compression. But with no gap, the valves need to be (adjusted).
The bottom part of the (stem) is the lifter, the upper part is the valve, you have to measure the distance between them, Take a screw driver and lift up on the valve spring to see the gap. Then you will know where the measurement is made, between the two parts!
Yes, until you can get the proper clearance, Do NOT take but a slight amount at a time, and while valves are out, reseat the valves in the block.
I sent the service manual. That is all the help that you should need to get the basic points. You can grind the valve tips with a sharping stone or a good file, they don't have to be perfect.
I work out in the country and always try t figure out how to do it , without having to go to town! Like i'm stuck in the desert and have to get home! Good luck with it! Thanks,
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