!989 Honda civic 1500 c.c won't start,very weak spark,at the spark plug.. Just replaced the whole distributor with a rebuilt one,new spark plugs,new Bosh wires and battery is fully charged,and even had jumpers hooked up for additional help,still weak spark.. Had car parked and unused for 4 months in the sun and weather,I understand that the main Relay can go bad in the heat,would that cause a weak spark...

Replace the coil. The problem is not main relay related.

You must not know Honda Engines,I stated that the distributor was replaced with a rebuilt,then how can it be the coil,when there is a brand new Coil in the Distributor.. that's right,the coil is inside the rebuilt Distrib.