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rjanderson9

16hp Briggs lacking in Compression

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rjanderson9
Hi, I have a Simplicity 5216H, it's an old tractor, but I just replaced the head gaskets, spark plugs, and air filter. I cleaned the valves, seats, and piston heads. Once I put it back together, I found that I can turn the engine by hand. I am not sure if I was able to before the work, and I hadn't tried it. Is this most likely to be an issue with piston rings or valves?

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RedbarnRick
Pullout the plugs and crank it, do you have equal pressure popping out of the plug holes? If yes it's ignition, if no it's head gasket valve stuck or rings. Do a compression test, if you dont have a tester hold your thumb over the plug holes one at a time and see what kind of suction and compression is in each cylinder, if you find it's ignition reset your points and replace the condenser, and inspect the wires for cracks.

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rjanderson9
Before replacing the head gaskets and cleaning the heads, it ran, but it was rough, and it was obvious that something was wrong, right up until it died. I ran it just long enough to load it back onto my trailer.

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rjanderson9
The Compression seems even, I don't have a guage, but I ballparked it. The spark plugs show a little spark, but it doesn't seem to be a very strong spark. I just rebuilt the Carb and will be trying that out later today. Does anyone have a wiring diagram or something along those lines for this tractor to tell me any kill switches and such?

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RickS
check the spark again. If the spark is weak, the tractor will not start. Use a spark plug you know works. Don't assume if the spark plug sparks it will spark under compression. Also spark plugs have been known to be bad right out of the box. Based on what you have stated it sounds like the problem is electrical; meaning the spark plugs are not firing properly. Try new points and condenser. Rick......

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sovereign72
If the tractor has spent any time stored I would remove the top engine cover and look at the condition of the flywheel andcheck for rust on the face of the coil and the flywheel magnets. if they are dirty I would clean them up and regap the coil then check spark. that has fixed more than one for me without buying a new coil. also remove the kill wire from its ground and see if the spark gets any better.

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rjanderson9
OK, so the rebuilt carbeurator is installed, and it runs, but if I touch the throttle trying to speed it up a little, it races and when i throttle down it backfires and scares the neighbor kids... What am I doing wrong with the adjustments?

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rjanderson9
So the safety switches keep the starter from turning, but won't shut it off. This diagram has given me a much better understanding of what I'm dealing with, I appreciate it. Thank you, RayS.

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