At Wits End

[nomad]

The old Briggs and Scrap Iron engine......

I recommend buying a goat!

We had a JD with the same engine that gave fits till, as Rohan recommended, we discovered that fuel tank cap vent was plugged by some small insect.
Sounds as if your problem might be the engine. Toss in some Marvel Mystery oil. Can't hurt.

[USA64]

The old Briggs and Scrap Iron engine......

I recommend buying a goat!
.

Get a sheep! Goats will only eat the bushes, flowers and the bark off the trees. Ask how I know.

[bulfin]

An update: pulled the engine; it is now on a bench with the valve and sump covers off. I inspected the valves, end caps, springs, rocker arms, rocker arm retainers, push rods, tappets and cam - no apparent problems. Put the valve train back together and set clearances. Then I turned the flywheel by hand for a few minutes. Rocker arms were loose and clearances way too large! I repeated the experiment, but this time marked the position of the studs the rocker arms sit on and also the retainers. There was no movement!

So where is the slack in the valve train coming from??

Maybe I will get sheep.

Bob