I have a 20.5HP Briggs and Stratton engine that turns over once or twice, then doesn't do anything else. New battery, all leads cleaned (battery terminals, solenoid leads, starter lead). The engine is about 10 years old. I don't know a great deal about small engines, so please keep it in layman's terms. Thanks!:confused:

May be a corroded cable leading form you batt try replacing those

Have your valves adjusted.

Replaced the battery leads and solenoid to starter lead. Unfortunately, no luck.
I'll look into having the valves adjusted.

Does anyone think it may be the starter? Is there an easy test for that (without buying an expensive diagnostic tool)?

Have your valves adjusted.

I have the engine broken down to the point where I have removed the valve cover. I get a side view of the valves, but can't see any rocker arms or lock/adjust nuts. Where do I go from this point? It is a Briggs & Stratton model 461777, type 0137 E1.

Also test your starter in case it's drawing too many amp(have it done at a shop)

Checked the valve clearances, and they're perfect (TDC-quarter of an inch method).
Cleaned the cylinder heads, valves, and spark plugs (there was a lot of carbon build-up).
It now turns over twice then stops. What next?

JMP2204, explain why the starter getting too many amps could cause this? Just curious...

Did you Try A compression test

Starter is dirty. Same problem after using my tractor on dusty soil. Running is a dust cloud. The starter stopped working. Everything else was good.

Change your starter. The top bearing in the starter gets wore out and allows the starter to drag inside. It acts like the battery, but it's the starter itself. I have come across this a lot of times with customers mowers with this same issue.