Have a starter that on cold start works perfect. After warm up, first turn of key motor sounds locked, second turn of key spins fine. It has been mentioned to me that a timing issue may cause this. Possible? If so advance or retard. All electrical seem's to check OK......Thank's, also if this is the case and anyone has time a short expaination.

 

Absolutely can be a timing issue. Base timing too far advanced . So the fuel/air ignites before absolute TDC, stalls the starter and cyl stays under very high pressure a while
But do you have obdI? Can you adjust timing? Otherwise it's an ignition fault somewhere.
Weak starter/battery resulting in low cranking speed will do same thing without actual ignition.

Caution: also a sign of hydrolock due to blown gasket. Look close.