March Air Conditioner Pump Hose Connection Issue

[Monheganlover]

I recently was attempting to winterize the air conditioner that came with my boat. It is a Cruisair unit that is mated to a March LC-2CP-MD Mag Drive Pump (see photo). The outlet hose to the air conditioner had been bonded so tightly to the outlet port on the pump, which is only 1/4" threaded plastic, that the port on the pump snapped off when I tried to remove the hose. The tech that installed the pump was, apparently, unable to find a Marelon 1/4 inch female to 5/8 inch hose barb that would fit the hose going to the AC unit. So, he attached a bronze 1/4" female to `1/2" male hex fitting to the pump's outlet port and, I guess, tightening the bronze fitting to the pumps outlet port weakened it. I ordered the replacement part for the March pump, which, also, comes with the same 1/4" outlet port. Unfortunately, I can not find a Marelon 1/4" female to 5/8" hose barb anywhere to thread directly onto the outlet port. I could, I suppose, do as the original installer did and attach a bronze fitting again to take the 1/2" Marelon hose bib. But I am reluctant. I have found on Amazon a nylon 1/4" female to 1/2" male fitting (see photo) that I could use instead of a bronze fitting. The 1/2" Marelon hose bib could attach to this. However, my AC pump is installed below the water line. I understand that fittings below the waterline in a salt water (Ches Bay) environment are, ideally, supposed to be either bronze or Marelon. Do people think it would be acceptable to install a nylon fitting to the outlet on the pump to then take the Marelon hose bib? The pump housing itself is polypropylene so, presumably, matching that up to nylon or polypropylene fittings would not be unwise. Advice?

 

[colemj]

No, you don't need marelon or bronze there. I think the pump body is nylon, not polypropylene, but I could be wrong on that.

You have the option to make the transition to 5/8" hose anywhere along the run, so you could use a 1/4"NPTF-1/2" Barb on the pump, a length of 1/2" hose off of that to someplace where you install a 1/2"-5/8" connector of whatever type makes sense. That could be a simple barb-barb if just splicing the hose, or if you have a 3-way valve installed for burping the air from the pump, you could just connect 1/2" to one side of the valve and 5/8" out the other side.