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  #11  
Old 04-28-2014, 09:30 PM
44DCNF 44DCNF is offline
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Could you have blown a head gasket from the sudden shut down of a hot motor at high speed? Heat soak? If I understand you right you did synch the throttle and choke. That mis-adjustment caused the similar symptom for me and I believe it had initially stretched the cable or threw it out of adjustment in a sudden snag on a pine tree branch. Did you maybe react and throw the throttle lever quickly when this happened?
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  #12  
Old 04-29-2014, 07:49 PM
Lumien Lumien is offline
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44dcnf: i don't know what you mean by syncd the throttle and choke. i have one throttle/choke control with choke at the top followed by high speed then low speed. when it happened, the blades stopped, then i moved the throttle from high to low speed and hit the kill switch. i guess i probably did it fast.

update: i took the flywheel off and the key looked fine to me, so i reassembled everything. took out the spark plug and it did look wet. wiped it off and used a steel brush on it to clean it up. i pulled it a few times with the spark plug out. put the spark plug back in and attempted to start. it did not start, but it there was a pop here and there. I am starting to wonder if maybe the kill switch stuck - when i bought the mower the guy had a small piece of wire attached to the spark plug and he was grounding it to the muffler to kill the engine. i pulled that wire out when I found the kill switch. maybe there was a reason the guy wasn't using it.
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  #13  
Old 04-29-2014, 08:14 PM
Lumien Lumien is offline
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update: now it doesn't try to start when i pull it. the spark is yellow (should it be blue)? i'll probably replace it anyway, but what do you think? Also, i removed the gas line (its gravity fed) from the carb, and gas flows freely through it when i open the line up from the tank. there is a clear gas filter inline and it looks ok.

getting pretty frustrated. i don't really want to take this in for service, but i may have too.

i have not yet attempted to clean the carb, as it just doesn't make sense to me that it would be running just fine, and then suddenly the carb is gunked up. is this a reality?

lumien
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  #14  
Old 04-30-2014, 12:06 AM
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unkownfl unkownfl is offline
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Put a new plug in just in case you screwed up the last one trying to clean it. While the plug is out check the compression. You can rent one for free with just a deposit at the major auto parts stores. I'm thinking the valve timing is off and you will have next to nothing for compression. If the compression is good then you can open the carb butterflies and let it sit for an hour or so. After that spray 1-2 second spray of starting fluid in it and see if it cranks. If it doesn't run on starting fluid its not a carb issue unless you have an obstruction in the intake manifold. If it was your kill switch you wouldn't have spark because what it does is kill the spark so the engine shuts off immediately.

You checked spark and its present.
You check fuel and even sprayed fuel so it's not fuel related.
Next is the compression. If there isn't enough it won't run.
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  #15  
Old 04-30-2014, 04:46 PM
Lumien Lumien is offline
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update:

There was no compression. I pulled the cylinder head and the valve cover. it looks like the intake valve has a stuck tappet. the valve itself slide freely in its guide.

I am WAY beyond my knowledge level at this point! Any ideas on how to deal with this? should i just try penetrating oil and attempt to push it back in? do i need to disassemble more of this motor to properly remove/clean/replace the tappet?

lumien
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  #16  
Old 04-30-2014, 05:22 PM
Lumien Lumien is offline
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another update:

ok, im not really sure what is going on with the valves. the exhaust valve seems to work properly, but the intake valve can actually be pulled out by hand (but it is retained by the motor). so, does this indicate that the actual valve rod is broken or am i missing some kind of retention because the exhaust valve can not be pulled out by hand.

lumien
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  #17  
Old 04-30-2014, 05:30 PM
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unkownfl unkownfl is offline
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sounds like the valve spring. Have you taken the side plate off to where you can see the other end of the valve. Pretty sure it's 4 bolts behind the carb if I remember right.
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  #18  
Old 04-30-2014, 06:04 PM
Lumien Lumien is offline
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yes i can see the springs. they look intact.
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  #19  
Old 04-30-2014, 06:38 PM
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unkownfl unkownfl is offline
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When you turn the motor over are the valves working? The intake valve should open while the piston goes from top to bottom. When the piston comes back up both valves are closed (compression stroke) and while the piston goes back down should still be closed. Last, the piston should come back up and the exhaust valve should open. Now when the piston comes back down it should repeat with the intake valve opening. The springs should have tension on them keeping the valves closed on the compression stroke this is the second step.
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  #20  
Old 04-30-2014, 06:49 PM
Lumien Lumien is offline
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the exhaust valve seems to be working. the intake valve is not. without removing the spring, its hard to tell what is broken - and nobody around me carries a tool to remove the spring. i may need to attempt it with just pliers. i can, at any time, grab the actual intake valve and push/pull it in and out. it travels much farther than the exhaust valve does. it looks like the valve rod is resting on a tappen that is not moving but with the spring in place its hard to tell if I am correct or not.

lumien
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