BS Got Me Befuddled

[ecopeland]

I have a BS 445677-2188-G5 (24 HP) that has me at my wit's end. It's on a Craftsman riding mower. The engine starts fine but after it warms up (10 - 15 mins) starts to have issues. I have checked the fuel lines, replaced the fuel filter, swapped the fuel pump, and cleaned the carburetor twice. I noticed today that when I pinch the vacuum tube from the valve cover to the fuel pump that the engine runs fine without any issues. It would seem that this would have the opposite effect and reduce the amount of fuel going to the carb. I didn't totally restrict the vacuum, just reduced it. The engine has 300 hours and never had a valve adjustment. Would the valves being out of spec make too much pressure causing any fuel pump to not function as it should? Here's a link to a video with the engine running to give you an idea of what's it doing. BS Engine Running

 

[Scrubcadet10]

when the engine starts running rough and wanting to die, i would remove the fuel output line from the pump, either at the pump or carb and see what the flow looks like.

 

[Tinkerer200]

Well that engine was due for a valve adjustment a good 200 hours ago so why don't you start with that and go from there?
Walt Conner

 

[Hammermechanicman]

Not much to go on. Possible blown head gasket.

 

[tom3]

What do the spark plugs look like? Evenly tan colored, black, uneven, snow white insulators?