Repeat of Compression Relief Failure Causing Choke-Sputter-Die, or Both?

[woodstover]

take the valve cover off and spark plug out, spin the engine over by hand and look for the intake valve to bump open slightly after the full intake stroke and the intake valve completely opens

Also time to check and adjust valve clearances if necessary. Only adjust valve clearances on a stone cold engine.

 

[Scrubcadet10]

Also time to check and adjust valve clearances if necessary. Only adjust valve clearances on a stone cold engine.

 

[Sears L2000]

Top valve a snug 4, 0.004”

Bottom valve at +/- 10, 0.010”

Reset both to 4.

New spark plug.

Have to get valve cover sealer to reattach.

 

[Auto Doc's]

Just to clarify, both valves are set to .004" now? If so, that should be sufficient.

 

[slomo]

I would drain the gas tank and install fuel from another gas can

Finally a mention about where all this starts at.

Do you have an old gas can with an open spout?


Or a new can with the EPA struggle your azz off trying to fill a mower up spout?

 

[woodstover]

LOL

 

[Sears L2000]

Yes. Both 0.004” feeler.

Five gallon yellow cap top with breather air tube.

Already drained tank and lines when I replaced the carb and fuel filter. Used new Marathon station 87 car gas.

 

[grumpyunk]

Run and stall sure sounds like a fuel flow problem to me. Ima few years behind you but still able to do a lot of things I expect will be more limited in a few years.
I would remove the fuel tank, and check the outlet fitting for debris that can get drawn to the outlet by fuel flow and restrict the flow.
You could test the theory by using a portable IV style fuel feed direct to the carb fuel inlet. If it quits its misbehaving it might well have some junk in the tank, so to speak.

Seems to me, unless there's a lot of gunk in the sump, sludge style stuff, the CR should work pretty reliably, and it has for umpteen years. (I am apalled at $800 for a cam swap) They generally don't flip flop too much, and when they fail it is a broken bob arm that removes the weight that allows the CR to quit dumping compression. Sometimes it eats the cam, etc, and you get to replace the engine/etc.
Any way, I would try an independent fuel supply, after checking that the float moves freely inside the float bowl. A partially sticking float could deny fuel flow, then after sitting, drop, and allow fuel to refill the bowl, and off you go again. My old geezer mower seems to suffer from vapor lock on hot days, causing the pump to push bubbles to the float bowl. Once it gets hot, I have to remove the hood, and sometimes that will make it run properly, sometimes it will gargle on with disturbed fuel being ingested, and it does not like that. Solution? I will run the fuel around the top of the engine rather than across inside the blower housing.
Check your fuel supply situation.
tom

 

[Sears L2000]

Update

-New spark plug
-Adjusted valves per above and replaced valve cover sealing
-Fully charged battery
-Fuel line and filter visibly full of gas

Now
-Cannot turn engine top by hand
-Mower battery alone cannot spin engine past compression
-Jumper cable addition of trolling motor battery spins it overcoming compression
-Fully choked, starts easy and
——-Runs five seconds, slows one second, stops
——-IF you immediately restart, it runs for 5 seconds, slows for one second, stops
——-IF wait 30 seconds
—————Exactly the same
—————Runs 5 seconds, slows for one second, stops
——-
——-IF throttled down choke off to wide open, runs perfect for 5 seconds, slows for one second, stops

Why do I think I am loosing?

 

[grumpyunk]

Is it possible your muffler got filled with mud dauber buildings? They will find semi protected spots and start to add mud if not disturbed. That could cause exhaust gas backup/back pressure that would make the engine able to run for a while and then ... not.
Had that happen on a SYM Super 9. Would run, then stall.. until I used a garden hose and screwdriver to muck out the dauber nests in the muffler.
tom