Hi group, my riding mower is hard to start. Starter can barely turn the engine over past the compression stroke. Have to turn the key a couple times to get it to go past compression then it will start to spin continuously instead of just half a turn. Tried jumping it from my truck and the starter still would stop at the compression stroke. Replaced the battery and solenoid also. Sounds like the starter I know, but it has done this since new in '98. Now its getting worse. What about the valve adjustment? Thanks in advance