It pumps only to the left carb so I think it's one of the diaphragms. Or is it something elseA new pump will cost you around 40 bucks. A rebuild kit is around 8. Doesn't look like there is anything missing on that pump. Why do you want to change it? Is it just not pumping? Check the pulse line from the engine to ensure there is no cracking as this will cause low fuel pressure. If you suspect the pump is causing an issue with the way it runs, pressurise the tank by blowing in it. Ensure you do it long enough to fill the fuel bowls. If the sled runs fine until the bowls get low, it may be the pump. Be sure to check your tank vent line for blockage as well. You should hear air coming from it when you blow in the tank. Hope this helps.
I kinda already ordered a new one because someone told me he has tried installing those rebuild kits and they have never worked. If anything I can return it. The new pump costed about $25Disassemble the pump, clean it and install a rebuild kit. It will be as good as new.