Gary you need: HELLA Relay- 996152131
You can find them on ebay, or Summit Automotive has them in stock in the US for $40.?
This is a sealed delay OFF relay, selectable from 0-900 seconds. You will likely need between 10-15 seconds. (be careful, there is a similar part number ending 151 that is delay ON, you don't want that)
Basically, you remove the leads from old relay and slide on to new, modifying the wiring to split ground and power. A wiring diagram for the relay is hard to find and doesn't come in the box, so I've included it with a few pics. If you note my install, you will see ground split between relay and pump with a butt connector and heat shrink. Not shown is constant power split in the same way between relay and a lead from the float switch(non-polar, so either switch lead will work). The other float switch lead will tie to post 15 on the relay.
The beauty of this relay is it allows you to adjust the time to drain the sump dry, keeping it much cleaner and much better smelling. Plus it's about 1/3 the price of the Scheiber. ;)
Set the time by turning the screw on relay(and switching dips switches as necessary), to leave a little liquid in the line. That keeps the gusher pump from running dry and also keeps the prime so it doesn't take as long to start up on next use.
I've also included a pic of the Side Mount Horizontal Float Switch(for those that need to add a switch and relay to other locations on the boat) For example, my 500 had only manual switches in the?port side heads.
I found the exact same switch as the factory on ebay two for $9. It shipped from China, so I had my doubts, but they ended up being identical to what was there, and only took to weeks to arrive. The size you are looking for is m16 body, and 92.5mm long, or roughly 3 1/2 inches.
As a final note on the float switch, if you mount it a little closer to the bottom of the sump than the Lagoon install(not too low or it won't turn off) it's easier to find the exact timing to leave liquid in the line, but still fully evacuate the sump. I also retained the manual button in my retrofit installs, just in case of a failure. As always, keep a spare switch and relay on board. Cheap, and you'll be a rock star when one dies and you have guests on board.
Hope this helps!
--
? ? Jim Oates? ? Reliant? ? Lagoon 500? ? Hull #133? ? Marina Del Rey
