Replacement fuel cap for an old Johnrude 3hp

Recently picked up one of these and the gas cap gaskets are shot and don't look to be repairable. is there a modern day equivalent gas cap that would work. Needs to have a breather that can be closed for transport.

Many thanks,

Lee
Huntsville Ontario

Chances are it is not shot.
Gaskets for that cap are available through any Johnson or Evinrude dealer. Dealer may have to order one for you. Seaway marine is another source for you.
The cap, should you need a replacement, could be available through the https://www.aomci.org group. Post a message in the 4-sale (webvertise) area. Don't forget to add your location to the header for the ad.
As to the cap, should you obtain the gasket..... there is a tiny vent in either a single or two locations up under the vent screw on the cap. Open the vent screw and take a piece of copper wire and run it down through each vent. They have a tendency to plug up after years of non-usage.

Good idea on the copper wire. Those caps have two gaskets. Check the little one under the vent valve too.