Not a downside exactly, unless you consider a never ending job to b a downside. There is a better way: replace the thick synthetic grease that's in every toilet pump when it leaves the factory and lasts at least a year.
Buy a tube of thick teflon grease (SuperLube makes the best one)...remove the top from your pump--which, depending upon the age of your Jabsco
, requires removing 6 screws or removing a hex nut. Stick the nozzle on the tube into the pump...give it a HEALTHY squirt...put the top back on. Pump a few times to spread the grease all over the inside of the pump cylinder...you're good to go for up to a year.
PH pumps: you have take the pump off the base, which requires removing 4 screws, and stick the tube nozzle into the bottom of the pump.
Takes all of about 10 minutes...I recommend making it a part of spring recommissioning as PREVENTIVE maintenance
I finally found out where the practice of putting veggie oil
into toilets originated. The first marine
toilets didn't have rubber parts
...their innards were LEATHER, which--unlike rubber--absorbs oil
. So neatsfoot or cottonseed oil was flushed through the pump when the toilet could sit for at least a few hours to let the leathers soak it up to keep 'em soft and supple. When rubber replaced leather (there are still a few very expensive manual toilet still do have leathers, btw), people just kept pouring oil down the toilet even though it's pretty worthless in today's toilets 'cuz all the oil just washes out in a few flushes.