the 400s guzzler comes with a internal return spring and is set up to be foot operated. Note that the 400/500 guzzlers are lever operated and the 400s/500s are foot operated.

Paul

> Hi there.

> It looked to me like the only difference between the Guzzler 400 and 500
> was the size of the inlet/outlet: 1" for the 400, and 1.5" for
> the 500. The pump bodies are the same size, about 5" diameter. I'm
> going with the 400 just because the smaller tubing required will be easier
> to install.

> In the pcarter site mentioned earlier, using a bungee for the return
> stroke, i.e., the suction stroke, seems easier to figure out than getting
> a properly configured metal spring to mount internally. It only has to be
> strong enough to lift water up into the pump body, not very much in a
> kayak, a couple of inches. My starting point will be trying 12" of
> 1/2" bungee; I think this will be close enough. A point to keep in
> mind may be that any "excess" force the spring or bungee
> generates will have to be made up by you with every stroke, so the biggest
> or strongest spring available may be more than what you want. I'm thinking
> the bungee thing can be made adjustable to find the best balance between
> foot effort required and speed of refill on the suction stroke.

> The Guzzler pumps are small enough to fit the forward bulkhead. For the
> conventional footbraces this won't be a problem, as it could go right
> between them. For braces in the form of a large panel, as in Nick's book,
> I don't know how you'd do it, but there's got to be a way.