Head gasket?

[Kparent]

poulan pro riding mower cut out while mowing. Would not restart. Made loud popping noise when turning over.
checked compress in both cylinders. 30lbs in left and plug covered in wet oil. 120lbs in right cylinder, plug normal.
suspect head gasket, our local repair shop on vacation this week

 

[bertsmobile1]

Sounds like it
Remove the bad plug and see if it starts
Remember to ground the plug lead

 

[Kparent]

Sounds like it
Remove the bad plug and see if it starts
Remember to ground the plug lead

turns over, doesn’t start but doesn’t cut out like it did when trying to start it with the plug in

 

[ILENGINE]

Or my other thought is one of the heads has overheated and dropped the valve seat and is holding that valve open. Should be easy to find because the push rod will be laying loose if it just happened.

 

[Kparent]

Took valve cover off offending cylinder, the aluminum push rod fell out in two pieces. There was no other push rod.

 

[slomo]

Where's the exhaust pusher rod at?

 

[hlw49]

In the crank case. These engines are noted to do this. Have a friend that says he has an engine with 3 in the crank case and still running. I got one that had one in the crank case took it apart and found the steel push rod laying on top of the cam gear bent like a paper clip. It did no damage to the rest of the engine. Put in a new push rod and engine runs fine. Still going.

 

[Kparent]

Was able to remove bent pusher rod from crankcase with magnet. Replaced cylinder head and rods. Ran rough when starting. Checked rods in opposite head, both bent. Replaced them. Engine runs very smoothly.
however…one final problem…engine turns over most of the time but sometimes i turn the key, the engine begins to spin but stops abruptly. at This point the flywheel is hard to turn by hand but once it gets past the top of the compression stroke the engine will start with the starter.

 

[Kparent]

My engine is a Briggs and stratton 441777 0726 e1.

 

[Scrubcadet10]

make sure your valve clearance is set properly