20 year old EPDM roof on 34' RV. Purchased this year. the roof looks in fairly good condition. the black is starting to show through in places but there are no rips or holes.. I have some repairs to make on the roof and want to wait until spring.. 2 of the repairs will involve replacing rotted wood, the rest will be slitting the rubber roof where it has lifted to apply glue (mostly around the edges), I've already recalked where necessary with Dicor self leveling calk to protect for the winter. I was going to apply 303 aerospace marine sealant to the roof for further protection for the winter but now im thinking that it may not be a good idea. If i use 303, will i need primer? If i do not use 303, can i skip the primer? Thank you for your replay. Sincerely, Rick.