Marinette Boat Forum

Hello

I am having trouble finding a replacement cap for our Jabsco waste pump out. It is the large fitting. The outside cap diameter is 2 1/8" and the thread is 1 7/8". I searched online and all seem to be too small. Any suggestions. Here's some pics.
Thanks

Looks like it might be one and a half inch pipe thread. You can get plastic or stainless plugs. Take the old one to a plumbing supply house and find a fitting the plug fits, then a new plug that also fits. A pipe thread will have a taper ( 3/4 inch per foot ) a machine thread will be straight. Yours looks like a tapered pipe thread.

MSC, McMaster Carr or Grainger should have what you are looking for. It is a pipe thread so once you know what size it is (i.e. maybe go to the hardware store and get one that fits.) then look them up and order the one with the best looking outside shape. Hex square or key style they make different head designs.
Good Luck!