Hey Stream no problem at all!! I actually realized your post wasn't bad at all and that you were one of the guys trying to buy "my" boat before I got to it. Ass hole all the time between friends!! No worries at all, now get your Checkmate sold and find an AT man!! They are truly a friggin war machine!!!

Come on man.......that was funny! For those of us that spend too much time on these forums that is EXACTLY what we see on a regular basis. Not saying you are, but it happens a lot.

BTW: Congrats on the boat, I love the lines of the AT. Just need to work out a 1/2 price special on that new 29 O/B model!!!!

You buy one for 1/2 price and I'll buy the next one for 1/2 price!
That way Pat will get 100% of the money!

Hey Guys, I work for March Pumps...its probably the most common pump you'll find out there in a marine A/C system....let me list a few common mistakes i get calls on all the time:

These pumps are not self priming so they need to be mounted BELOW the water line to prime them.
They CAN NOT be run dry for extended periods of time or you will start to melt things (it is a plastic pump)
Mounting/orientation is important with these units....ideally they need to be mounted horizontally with discharge facing up....you can mount is vertically like on a stringer/bulkhead etc....but the intake will need to be on top with motor below. (still below the waterline though)
The LC-3CP-MD is the most common pump out there and is rated to handle up the 24k BTU's total
If you are under 6k BTU's then the LC-2CP-MD pump will work just fine
If you have a bigger system up to 48k BTU's then the series 5 pumps are the choice.
If your bigger then 48k BTU's then give us a call and let me know how many units you are trying to cool and make sure you know how much water in gallons per minute or hour each units needs minimum....we make pump that can go up to 210gpm if need be

As far as trouble shooting the pump here's a few tips:
just because the motor is "humming" doesn't meant its spinning! the rotor can be locked up...if the units is humming verify the impeller is turning by looking down the hole from the discharge. If not turning then you need to take the pump apart and inspect further as to why.
The impeller should spin freely on the shaft....on the front part of the impeller is a groove...looks like you can put a flat head screwdriver in there. That's our wear indicator....when new its about 1/8" deep....if its about gone then time for a new impeller. If the impeller binds on the shaft it may be crud...clean it well and try again...if still binding then the pump may have been run dry and there's some damage. You can drill it out with a 17/64" drill bit and that will open the bore up...it will make it slightly noisy but wont hurt performance or life.
If none of the above get you going then call us here at the factory and we can try some more things to check but more then likely it may be a bad motor.