hot start problem

[scott_f4i]

ok guys , i need some help on this one . im having hot start problems on a f4. turns fine when its cold , or been sittin for like 20 min - 1/2 hour . but if i stall it and try to restart its acts like a dead battery . ive tried different batteries , changed the ground and starter positive wires , thought the starter was heat soaking so tried that . i cant figure this issue out . it will jump start fine , but wont crank when its hot. every sensor , and both harnesses have been changed , and it still does it .
all the problems started when i changed engines . ever since i have been fighting this problem . thanx in advance .
scott

[SKETCH]

Wuz Up Man, If You Have Replaced The Wiring Harness,regulator Rectifier And Batteries.you Might Want To Check Your Stator And The Magnet Around It.especially If You Didn't Have A Problem Until You Switched Motors.if You Have A Multi-meter Set It On Ohms Go From Highest To Lowest While Testing And Check The Three Yellow Stator Wires Make Sure They Have The Same Resistant And Do Not Ground Out.if That Checks Out Your Magnet Might Be Trashed Take A Feeler Gauge Around A .003 When It Attaches To The Magnet Make Sure It Have Sufficent Drag On It Or If There Is Any Doubt Just Replace It .short Of That Id Make Sure Your Getting No Less Than 13.21 Volts When You Rev. The Motor.hope This Helps,email Me If I Can Help