I have a Murry mower that won't turn over, I have new battery I tested with volt meter its OK. It makes a clunk sound when you turn key on but will not turn over, I bypassed the seat switch, the blade switch, the brake switch still same result. I tried to bypass solenoid with jumper cables directly to starter it made a faint spark but did not turn over and the clunk sound stopped for a few minutes after that when I turned the key. After a few minutes the cluck sound returned. I tried to jump across the solenoid with same results as above, thinking it might be starter but not sure.

Try removing the spark plug to see if it turns over at all with no compression.

OK, new development I can short across the solenoid and mower starts

Hi,
That ought tell tell you that the solenoid is bad. One of the most failed parts!
Peace,
Clarke