Briggs 4hp Horizontal not running just right

[skippymud]

Hello All
Briggs 4hp horizontal not running just right. 1976 model 100292 on a Troy-Built tiller. VID:

Flywheel key is intact
Good compression
Carb is rebuilt 100%. I actually tried 3 different carbs and got the very same result
Bowl in tank has plenty of fuel
No leaking fuel
Has good spark
As you can see in the YouTube VID, it just spits and sputters. It idles but only for a short time. When I REV the engine, then it sputters
I welcome any suggestions as to the wrong-goings

 

[ILENGINE]

Being that age of engine when was the valves regrind/lapped and the clearance reset. The old L series Briggs engines will wear the face of the valves to the point that will float the valves.

 

[skippymud]

Thanks ILEngine. Will new valves cure the problem?

 

[ILENGINE]

Thanks ILEngine. Will new valves cure the problem?

New valve will still have to be lapped into the valve seats or the seats recut. And then the valve stems will need to be grind off to set the proper clearances.

 

[skippymud]

Great, thanks. New Valve Springs then too while I'm at it. Weak springs will result in valves not closing completely I believe