My Maytag washer will no longer advance from final rinse to the spin cycle in the "regular wash mode" It will advance using the "delicates" mode. My question is what do I need to replace, is it the timer, is it the timer motor or is there another part that I need to replace to get the washer to advance to the final spin?
It is probably the timer, but given the cost of the part and the age of your machine I would suggest you consider a new washer.
sidfink43 is correct, maybe time to look for a new one.
If you do decide to repair it you would need to replace the whole timer as you can not get just the motor that in mounted on the timer body.