It may just be that it wasn't as well lubed as it should have been when it left the factory. Or, 5 people living aboard
COULD be using the toilet enough to exhaust
the grease in the pump that quickly . However, there's no rule
that you can ONLY use thick grease to lube the toilet once a year...that's only as often as is necessary for most people. You can't spare 10 minutes every 2-3 months to do it? That's certainly cheaper and easier than pouring something down the toilet every other day! And if you schedule it as preventive maintenance, even once a month, your seals and o-rings will last a LOT longer!
But...your joker valve won't...it'll wear out much faster with that many people using the toilet every day. Most people should replace the joker valve at least annually...you should replace it at least quarterly. Here's why:
JOKER VALVE 101
Most people think that the only thing the joker valve does is acts as a check valve to stop backflow from returning to the toilet or odor
from the tank from escaping through the toilet. But that's not a joker valve's most important function...in fact, the joker valve is THE single
most important replaceable part in a manual toilet.
Here’s how the discharge half of the pump works: On the upstroke of the piston, a vacuum is created in the area beneath the piston. This causes the joker valve to close tightly, and the flapper valve beneath the pump to open, allowing some of the contents of the toilet bowl to be drawn into the bottom half of the pump. Then, on the down stroke of the piston, the flapper valve is slammed shut, and the effluent is forced out of the bottom of the pump, through the joker valve, and off down the line. But when the joker valve becomes worn and/or there's a buildup of sea water
minerals on it, it can no longer seal tightly on the upstroke of the piston...less vacuum is generated when you pump it. And as it becomes more worn less and less vacuum, till finally the bowl contents simply move up and down a bit, but don't go anywhere. Sometimes the flapper valve needs to be replaced too, which is why toilets should also be rebuilt at least every 5-6 years as PREVENTIVE MAINTENANCE.
You prob'ly won't notice the loss of efficiency at first because it's so gradual...same as we don't see that we've gotten a little older than we were yesterday when we look in the mirror each morning. But I guarantee you that if it's been two years or longer since you replaced the joker valve, you need to pump the toilet at least 50% more times to move the bowl contents to the tank or all the way out the thru-hull....IF they're getting there at all any more.
toilets have moving parts that require maintenance. PREVENTIVE maintenance is called that because it PREVENTS problems that have to be fixed. You get to do PREVENTIVE maintenance on YOUR terms, when it's convenient for YOU...unlike repairs
, which NEVER are needed at a convenient time.