If you want to stick with manual pump, I highly recommend the Raritan models. Worth the extra coin over a Jabsco model.
As far as the smell, it's very likely your hoses smell if they haven't been replaced. There is a test you can do -- take a wet rag and wrap it around your hose between the head and holding tank. Let it sit for a minute and take it off. If the rag smells, you need to replace the hoses.
Your holding tank is probably fine if it's a normal polyethylene unit. I'm not sure what Sabre used from the factory.
Lastly, if you want to thoroughly immerse yourself in the topic of boat odors this is a great book to pick up: https://www.amazon.com/New-Get-Rid-Boat-Odors-ebook/dp/B01BW2ZSTW/ref=sr\_1\_2?dchild=1
The New Get Rid of Boat Odors, 2nd Edition: A Boat Owner’s Guide to Marine Sanitation Systems and Other Sources of Aggravation and Odor by Amazon.com Services LLC Learn more: https://www.amazon.com/dp/B01BW2ZSTW/ref=cm_sw_em_r_mt_awdo_nt5HFb0FHCN15 Best book on the topic