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1990 3807 Head Fresh Water Pump

Posted: July 12th, 2025, 2:17 pm
by chuck1869
Hello All. First time posting here. We just purchased this boat about 5 weeks ago. The head bowls both were turning grey with water standing in them. I presumed the water was coming from the seacock. We were connected to shore water. I put water in the fresh water tanks with some water treatment. It seemed to clear up the bowls, but then the fresh water pump wouldn't stop running, so I turned the breaker off and went back to shore water.

Couple of questions. If I close the seacock, will it force the head water to come from the shore water?

I can hear the fresh water pump, but cannot see it. Sounds like it is forward of the forward fresh water tank. It runs kind of loud. Does anyone know how to access that pump?

Thank you in advance to anyone that may have some guidance.

Re: 1990 3807 Head Fresh Water Pump

Posted: July 13th, 2025, 4:12 pm
by buster53
Ok, I used to have a 3807. The steps leading down to the galley, there is a small hatch underneath the steps. The pump is located in that opening. I had to replace my pump once, not easy, but doable. Obviously, you have a leak somewhere if your pump is running, you just need to track it down.

Re: 1990 3807 Head Fresh Water Pump

Posted: July 13th, 2025, 4:12 pm
by buster53
As far as the head goes, it should only be using fresh water from either the shore or your onboard tank, or sea water. This is not an either/or situation. It is one or the other.

Re: 1990 3807 Head Fresh Water Pump

Posted: July 13th, 2025, 4:38 pm
by Viper
Unless there was a change from’89 to ‘90 or a previous owner upgraded, it will be a sea water flush, not fresh water from your potable water system. What type of head/toilet do you have?

Re: 1990 3807 Head Fresh Water Pump

Posted: July 13th, 2025, 9:22 pm
by buster53
[quote="buster53"]

Re: 1990 3807 Head Fresh Water Pump

Posted: July 14th, 2025, 6:30 am
by chuck1869
Thank you buster53 for the replies. One head is a Jabsco. Not for sure on the other. I'll look for the pump this weekend.

Re: 1990 3807 Head Fresh Water Pump

Posted: July 14th, 2025, 8:27 am
by buster53
chuck1869 wrote:Source of the post Thank you buster53 for the replies. One head is a Jabsco. Not for sure on the other. I'll look for the pump this weekend.


Good. While you are looking, you need to find all of your seacocks and strainers and identify what each one is used for. I had 7. Find all bilge pumps, probably 3 and make sure all are in good working order. Find both sump pumps, most likely, both need a good cleaning. Find all bilge access hatches, open up to see what they give you access to. Carver is famous for putting them in hidden, out of the way places, like underneath berths, inside cabinets, under galley steps, etc. Open up your AC returns and depending on the style of filter, clean or replace the filter and inspect the inside of the return as it may need a good cleaning/vacuuming.

Re: 1990 3807 Head Fresh Water Pump

Posted: July 14th, 2025, 11:19 am
by Viper
If you have to access your fresh water pump under the stairs by the galley, the bottom step is removable. There’s a metal bracket on both sides under the step. Undo the top screws and the step will come off, makes it way easier to work on the pump.

If your fresh water pump doesn’t stop running, you’ve either got an empty tank, the pump is faulty or you have a plumbing leak. Do yourself a favor, if you have to replace the pump, relocate it. I installed mine in the engine room on the forward bulkhead right in the middle where I can easily get to it. It’s an easy install and very convenient when winterizing.

Re: 1990 3807 Head Fresh Water Pump

Posted: July 18th, 2025, 5:34 pm
by buster53
FYI, you mentioned the forward, fresh water tank. Unless a previous owner did some modifications, that boat only has 1 fresh water tank and it is located underneath the aft berth. Are you sure you are not looking at one of the holding tanks?

Re: 1990 3807 Head Fresh Water Pump

Posted: July 18th, 2025, 6:58 pm
by KyleR
If your fresh water pump doesn’t stop running, you’ve either got an empty tank, the pump is faulty or you have a plumbing leak.


Also, some freshwater pumps, like our Shurflo Aqua King 2, have a pressure switch AND a bypass valve built into the pump, both of which are adjustable via a very small allen wrench. We had an issue with ours running for no reason and I ended up tweaking those setpoints until it operated correctly. There are videos on YouTube showing how to make the adjustment.

Might not be your problem, but definitely something good to be aware of! :-D