Lost prime on A/C seawater pump

[Sundancer Pilot]

I replaced the A/C on my 1993 Sundancer 290 yesterday. Got everything hooked up, then cleaned the seawater strainer on the pump. It now will not pump, so am assuming I lost the prime on the pump.
I tried several things, close the seacock for a couple of minutes, then open, leave the seacock open and let the pump run a few minutes.
Nothing worked. I don't find a prime button or any such thing on the pump, so not sure what to do next.
Appreciate the help.
Sundancer Pilot

 

[carterchapman]

I just loosen 3 of the four screws on the pump housing, start the A/C, and it will prime. Once water "squirts" out of the housing cover, tighten the screws back up and you're done.

Other folks have recommended to put a hose against the discharge outlet and "back flow" water to prime the pump.

 

[Quint4]

It is not self priming. Sometimes running the boat on plane will prime it. I had to disconnected the intake hose and fill it with water after cleaning my strainer.

 

[ohsnow]

I had great feedback on a similuar thread last week.
Drive her on plain is quickest in my book... and good fun to.
Only need a 5 minute ride.
Enjoy:grin:

 

[capecodcruiser]

if you loosen the screws of the strainer till water comes out is what worked for me. yes a little water in the bilge, but quick, easy and done. I tried the hose against the discharge line and it only got me soaked!

 

[Dick Whetstone]

I trailer my boat and "Back Flushing" the AC by inserting a garden hose with a properly sized nozzle into the AC water outlet is how I flush salt water from the AC in my 270 Sundancer after running in the ICWW. Doing this should also prime the AC pump.

My AC pump is a centrifugal pump. This may not work with an impeller pump. In fact it may damage an impeller pump.

 

[Bucit]

No need to even get it on plane. I keep my boat on a lift and lose prime every time. Run the baot at idle speed or a little faster. That will push water into the intake and then turn it on. It will prime every time.

 

[Loneranger]

http://clubsearay.com/forum/showthread.php?t=11794

I believe my post number 3 in the link above lists all the possible options available.

This one is asked and answered on at least a yearly basis. Another reason for a FAQ section.

John

 

[Sundancer Pilot]

Gentlemen, one and all,
I appreciate the inputs. Looks as if I have a lot of options to consider. I do like the thought of putting in a shut off valve that can be opened whenever this happens.
Thanks
Sundancer Pilot

 

[Luckydogs]

I would lose prime every now and then when i was trailering; I would take the intake hose off at the ac, turn the system on while holding yur thumb over it until water came out, turn off system and reconnect hose.

 

[Whitenights]

The garden hose/backflush tricks worked on my old 280 every time, kept it on a lift and had to do it most times. Just stick the hose on it for a few seconds and then turn it on, starts pumping right away.

 

[66pony]

I have found t hat using a shop vac on the through hull works in about 10 seconds. I need to clean my strainers once to twice a week and usually do it before I take the boat out. My daughter complains if the A/C is not working while I clean and prep the boat.

 

[Mark V]

I solved mine by determining the root cause for my particular case, although there are many work-arounds listed out there that will work to compensate. If your water lines aren't sloped properly - mine weren't- the pump just cannot flood as it should to get primed. Mine has never failed since I took care of the hose sloping/air trap issue. The post with the entire history on mine is;
http://clubsearay.com/forum/showthread.php?t=9345

I pasted my final conclusion here:

The fix, as hoped, was to simply re-route the water line between the seacock and strainer per Dometic's instructions and Sea Ray's very own diagram.......

The root-cause was indeed the straight hose-fitting coming out of the seacock rather than having the proper 90 degree elbow there, because the straight fitting forced the hose into an upside-down "U" bend on the way to the inlet of the strainer, thus creating a perfect place for an air pocket to remain, thus robbing the pump of any chance to initiate flow when first started.

After replacing the straight, upward-pointed fitting on the sea cock with an elbow, the hose is now somewhere between completely horizontal and slightly-sloped as it leads to the strainer, eliminating the previous trap for the air pocket.
I also "aimed" the new elbow directly at the strainer's elbow so the hose between them could be as short as possible, and straight with almost no bend in it at all. In addition, I used tie-wraps to lift 2 very slight low spots in the water hose from the pump outlet to the firewall - one near the batteries and one near the battery charger.

All of the tips folks sent in were excellent, and they do work to compensate for the problem, but I believe that in many cases, (probably all of the Sundancer 240's like mine) if the line slope is corrected, it's quite possible that none of the work-around solutions will be will be necessary. This is because the pump is indeed below the waterline, so when you set the boat in the water, water will flow into the pump and prime it as long as there are no air pockets stuck in the lines to block the natural flow (nor any other blockages).