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adjusting valves how is it done

#1

B

bouttree

Hi from the midwest,I need help adjusting the valves on a 20 hp briggs and stratton motor.
I'm a good mechanic on most problems but adjusting valves puzzles me.
The repair manuals instructions are not clear:
manual-move cylinder to top position fuel stroke. Question how do I know I'm on the fuel stroke position? Question How do I know which valve is fuel the top one or bottom one?


So far I trouble shot everything because the engine wouldn't start.I had broken a flywheel key(funny story my lights don't work,I was attempting to finish in the dark. the wife came out and told me to quit mowing,I told her I knew what I was doing! a few minutes later I ran over the dog chain and a metal stake!!!!!!) How do women do it? you don't listen, things go bad.
Everything checked out good so I decided to check compression(compression isn't a favorite of mine,never had to deal with compression before.) anyway I started attempts
on the valves. I don't understand the repair manual so I started guessing on adjustment. I got the motor running but no power and a lot of pop pop pop. I adjusted again, motor runs better but still pops.
I may have worn springs and valves but I want to adjust the ones I have before I try any thing else.
Thank you for helping me. Please save me from using the push mower to cut my 1 acre. Also I never told the wife I ran over the dog chain.


#2

M

motoman

Boutree, The story should be the dog dragged the chain under the mower. Fuel position is probably compression stroke. Use your finger to cover the spark plug hole while you turn over the engine. You should get pressure that moves your finger off position. Trace the exh pipe to the head which is ex port , the other is intake. Compression gauge screw in adaptor or rubber nubbin, open throttle butterfly while cranking. Youtube shows people using feeleer guages, but no one can tell you how proper drag of the feeler is known. Practice


#3

I

ILENGINE

Remove spark plug/s and the valve cover/s turn flywheel by hand while either shining light into spark plug hole, or inserting screwdriver/pencil into spark plug hole Turn until piston is at its highest point, and then starts back down, both valves should be closed. If not, then rotate flywheel one complete turn and find point where you are just past top dead center, and then set valves for that cylinder, and if you have another cylinder then repeat for the other cylinder. If single cylinder the intake will be the bottom valve, and the exhaust on top, if twin then top is intake and bottom is exhaust. These instructions are for Briggs engines.

When properly set the feeler gauge should have a light drag when inserted/ removed from gap.


#4

B

bouttree

thank you I will let you know if I get engine running


#5

B

bouttree

thank you, I will let you know if I get the motor running



Boutree, The story should be the dog dragged the chain under the mower. Fuel position is probably compression stroke. Use your finger to cover the spark plug hole while you turn over the engine. You should get pressure that moves your finger off position. Trace the exh pipe to the head which is ex port , the other is intake. Compression gauge screw in adaptor or rubber nubbin, open throttle butterfly while cranking. Youtube shows people using feeleer guages, but no one can tell you how proper drag of the feeler is known. Practice


#6

M

mechanic mark

Engine running?


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