YOu're the only glitch in your PHII pump...90 % of leaks are caused by over-tightening the bolts. The flange on the joker valve is the gasket that seals the discharge fitting connection to the pump. Over-tighten the bolts creates a pucker in the rubber around the bolt, causing it to leak....and the more you tighten the bolts, the worse it leaks. With any luck, the new pump and joker valve haven't been in place long enough for the puckers to become permanent...but if they have, you'd only need a new joker valve to solve the problem.
Start by tightening the bolts--both of them--only hand-tight...flush to check for leaks. If there are any, tighten both ONLY 1/4 turn more...check for a leak again. Repeat till no more leak.
You really shouldn't have had to replace a 15 yr old PHII pump...they easily last 20+ years when kept well lubricated, joker valve is replaced at least annually and gets a rebuild kit every 5-6 years (approx $60). I'v seen several older than 25 years. There are two different PHII rebuild kits--one for toilets built before 6/92 (PHRKII) and one for toilets built after 6/92 (PHRKIIC) and it's important to use the right kit because there are parts in both that are not intechangeable.
As for why you should replace the joker valve at least annually...
Most people think that the only thing the joker valve does is act 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.
--Peggie