after cleaning flametrap, hoses and box. I get a no start, checked wiring all look right. still no start. continue to investigate trying to crank, find rotor look a little rough can be changed, did that. distributor cap looks fine. tryed to crank,no start again. now starter will not turn. removed starter had checked, fine. checked battery, good. I need to know where yellow/blue wire connects on starter to trace connection back. Red ones look fine. has this happen to anybody else. do anyone have ideals why starter will not turn. will get to ignition problem after starter. cannot check for fire. thanks

Check 25 amp fuse in engine bay side of fender. check wires going into fuse holder. check fuses inside car. check condition of wire to crank position sensor just behind engine. check condition of wires to starter. try to "hot wire" starter to see if it starts.
wire diagrams
http://www.volvowiringdiagrams.com/?dir=volvo/240%20Wiring%20Diagrams/1975%20240%20Green%20Book%20Complete

update to problem, read archives and applied 12v to yellow/blue spade on starter. car started. does anyone know what system this bypass for I think this maybe where problem lay. thanks again

When you apply power directly to the spade terminal on the starter, you've by passed the ignition switch and the neutral safety switch.

The NSS is only used on automatics, and is located under the gear shift lever.

Peter

the answer is rotor button and bad solenoid on starter will replace starter. rotor already replaced. thanks guys. on to next problem wipers stop at half windshield any knowledge on that????

Check the ground for the starter motor. IIRC you have to take the little cover off.

Greg

neutral safety switch, maybe?

What wires are in proximity to the repair, that you might have leaned on or otherwise bothered