Force 85hp gear changing problems

Hi, i have an force 85hp outboard which up until last weekend was running fine with no issues! the boat hasnt been used for a while but decided to take it out for the day, on getting into the water the boat started fine, bit sluggish to start but soon warmed up.It reversed out of the slipway fine but when i went to engage forwards nothing happened except the engine revving,luckily with some persistance i managed to get back to the slip way but on removing the engine cover for closer inspection nothing ontoward can be seen.i know somethings wrong because its not working but cant see why it would engage reverse but not forwards? any advise on what i can do to sort this problem would be graetly appreciated. many thanks

Could be the cable is old?
The shifter old and the connections loose?
The connections on the motor need adjusting?
You have easy access to the prop?You cando this without running the motor.

If not,In the slip,tied tight or alongside the pier,tied tight.
Remove the cowl,unhook the connectors.Then start the motor.Shift it forward then reverse then into neutral.
Then adjust the connector so it moves to the motor.

Where the shift shaft goes into the lower unit , does it move when operating the control box?---Prop must be turned slowly while trying to shift. ---Is the connecting pin in place on the shift rod , found just above the lower unit ?