I have the same problem. Jc pump with place diverter. I was at elsinore yesterday too. Orange hallett

I called Place Diverters & controlls today and spoke with Tim, told him what is happening. His responce was they get a few calls every couple of years about this splash back problem. He said he can't explain what or how this is happening but what is happening due to many variables is that extra arm that the forward/reverse bucket cable is attached to is catching the water when slowing down and the water travels up that cable and flies off to the right bank of the boat. He recamended to install a large diameter washer under the nut replacing the small washer and it will act as a shield not allowing the water to travel up that cable. I really looked at the shape of that arm and it does look and sound logical, water does strange things sometimes. My boat with the origional Berkeley nozzle never did this, but since the place diverter and that extra arm is there, it does this. I really don't see a teflon O-ring causing a stream of water to fly up and over the transom. I'm going to try this fix, and I will pass on any info. how it does, but I won't be able to take the boat out for testing for a few weeks. When I do, I was thinking of going up to Irvine Lake, it's closer and the water is so much cleaner.

The entire place diverter comes complete and it's just a bolt on assembly, I questioned them today about this O-ring possibility, Tim rulled it out right away, and for right now so am I. The only O-ring that I could of put some lube on is the one that seals the diverter to the adaptor that changes the JC to a JG style with that Place Diverter, but that's really not a very tight seal. I even had that piece that goes between the bowl and the diverted powder coated and that didn't hardly make any clearance issues with that O-ring. Even if someone would spread some sort of lube on that O-ring, how long do you think it will last with all that water pressure going through there?

There is two sizes for the o ring and if your housing is really worn from sand..ect, you can put a rubber band/teflon tape under to raise it a tad for tighter seal.