Gear lever spring and pawl

Just getting my new to me 75 MK3 back on the road after 35 years of hibernation. I rebuilt the top end of the motor, had the primary apart for repairs, but did not do anything to the Gearbox other than change the oil and install a new neutral switch. On my 1st test ride the bike only had 3 gears, 1, N, 2, 3. could not get 4th. By putting the bike on the centre stand and rotated the wheel with the spark plugs out I was able to get it to shift thru all the gears once then it stuck in 4th and wouldn't down shift. Shift lever always moved up and down properly. Should mention that when I had the primary apart I did pull the gear shift cross shaft out to install a new rubber cover on the union.
Researched here and decided to take out gearbox outer cover. No broken pieces inside but shift pawl doesn't engage the ratchet plate reliably.
I can get it to shift thru all the gears by levering the quadrant with a screw driver. I ordered a new spring and pawl but I truly can't see anything wrong with the ones I have.
Any suggestions on what to do?