The center scupper plug for the Impulse Drive area can be purchased for your Mako kayaks here:
https://boutiqueborealdesign.com/products/foam-mako-center-hole
Thanks for reaching out about replacement foam scuppers and pedal-drive foam closeouts for your Mako. We have these scupper parts. For Mako 12 (or Lost Creek Angler 12 / Azul Triton 12) https://boutiqueborealdesign.com/products/foam-plug-kit-mako-12 ...
HI you can find the scuppers sold individually for the Mako kayak here https://boutiqueborealdesign.com/products/scupper-plug-with-hook-closed-2pcs Of the full kit for the Mako 12 is here ...
There are different variations and sizes of scupper plugs the Riot Kayaks For Riot Escape 9 series kayak you'll need the Large size ones here - sold in pairs. For Riot Escape 12, Escape 12 Angler, Escape 10, Escape 10 Angler and Riot Mako series you ...
We do not recommend using the scupper holes for the carts. The hulls are too heavy for that and may cause damage in the scupper hole areas. A wider heavier duty flat type cart is best with straps to anchor it in place. The scupper type carts can ...
See link at bottom to view and download the Riot Whitewater Owner's Manual from 2008. Works fairly well for info on current (since we have not changed them much) and older model (discontinued) kayaks.