GM Master head issue-she grinds but no water.

[RJM]

Well, if I didn't have enough on the "To Do" list, this a.m. the Master head decided that it didn't want to pump water into the bowl. Great... So, l am wondering where to start diagnosing this thing. Is there a separate water pump? Macerator spins just fine and with a quart container of water I was able to clear the bowl. The VIP and forward heads works fine. I am not looking forward to this, but oh, well. Anyone been here and what to do next would be appreciated!

 

[doc g]

I assume you have a Galleymaid , if so, the same motor that turns the macerator turns the flush water pump, opposite endes of the electric motor. I would check the strainer/thru hull and be sure you have water there first, then pull the hose off the flush water end pump and see that you have water to the pump. If so then close the seacock and buy a Galleymaid water pump rebuild kit and install it. I am not sure it may be an MR2 ?? . This could also be an opportune time to convert that head to freshwater flush.....Hopefully someone will jump in with the part #'s needed.......Pat

 

[jmooney]

It might have just lost prime . There is a priming plug on each end of the pump. Open the fresh water side and see if water comes out . Don’t run it dry . If no water comes out , check your strainer.

 

[RJM]

Yes, GM=Galley Maid. Thanks for the info. Looks like I have plumbing to check.

 

[MadHatter53]

Mine has a check valve the I need to remove and clean/rinse at the beginning of each season.
I tried a shop vac to try to open the valve with no luck.

 

[Captain Ralph]

Some heads have a raw water strainer. All clear?
If your going to invert your self and loose blood in the bilges, May as well go here also;
Next is to pull the raw water hose to the pump (smaller of the end hoses) and ensure green water flows.

When was the last time the pumps stators and/or rotors were serviced (replaced)?
If water is flowing, then take the end dome off and replace the stator, If the rotor (wierd looking screw) looks pitted or warn, replace it also.

 

[SEVEN]

Most likely lost prime. However you may have sucked up some seaweed or plastic bag. Shut the thruhull on the intake off. Remove the hose, then turn the thruhull back on to see if you have clear water coming in. If not remove prime nut and fill with water. If all that does not work you will need a new stator.

 

[RJM]

Well, I feel a bit sheepish-and relieved. To clear everything out of the pump I ran a couple of quarts of water through the system with the plan to tear into it today. Then suddenly this a.m. it started working again, just like old times. I am guessing that either there was a temporary blockage on the intake or the pump just lost it's prime and my pouring water in and flushing got it back. At any rate, I am thankful that I don't have to tear in/replace the head. Sometimes karma is on your side!

 

[jmooney]

Pouring water into the bowl will not prime the water intake side unless the priming plugs have been removed and replaced with tubing connecting the two sides . This can fill your holding tank however.

 

[JuiceClark]

The head in the master was empty and had lost prime after I had the boat out on the hard for some work. I suppose some yard employee flushed it, not realizing it's a raw water feed.

Anyway, I didn't want any of it turning dry. So, I filled the bowl with the hand faucet from the shower and let that run into the bowl while flushing. After about 30 seconds holding the flush button, prime was restored and all is good ever since.

 

[rwaldrop13]

The head in the master was empty and had lost prime after I had the boat out on the hard for some work. I suppose some yard employee flushed it, not realizing it's a raw water feed.

Anyway, I didn't want any of it turning dry. So, I filled the bowl with the hand faucet from the shower and let that run into the bowl while flushing. After about 30 seconds holding the flush button, prime was restored and all is good ever since.

I've had the issue with my remaining GM head (in the master also) occasionally losing prime after I pump out. I fill the bowl and then flush, restores the prime. Good thing, as the priming bolt on mine is so rusted into place I am afraid to try to remove it for fear it will snap off. We already replaced the midships head with a freshwater new-style, but trying to get by another year or so on the GM aft.

 

[JuiceClark]

I've had the issue with my remaining GM head (in the master also) occasionally losing prime after I pump out. I fill the bowl and then flush, restores the prime. Good thing, as the priming bolt on mine is so rusted into place I am afraid to try to remove it for fear it will snap off. We already replaced the midships head with a freshwater new-style, but trying to get by another year or so on the GM aft.

Ha, how about that. Turned out mine hadn't been flushed so long, the entire pump was corroded into an irrepairable mess. The ONLY thing which would move was the priming bolt. I took one out and water started gushing - barely could get it back in!

It's always something, but I kinda' like the old heads. They work fine so far, at least when the damned kids remember to flush.

 

[RJM]

Final update: It turns out that the rubber impeller for the flush water was dying. It's easy enough to replace with the available kit, less than $40. The kit comes with a new impeller, grease, nylon washers and two gaskets, depending on the model you have. I did pull the whole toilet, not just for this but to fix a base issue, but it really wasn't necessary. In place, you can reach the four bolts that hold it on, water supply hose clamp and the bowl feed hose clamp, which is all that you need to do to pull the body off the shaft. Once off, you remove the old impeller, inspect and wipe down the inside of the housing and lubricate liberally before inserting the new impeller according to their directions, making sure that the impeller can spin clockwise. Just note how the vanes are positioned before removing the old one. I always take cell phone pictures along the way-who would have thought that cell phones could be so useful?! Once you are ready to reinstall, be sure to note that the impeller has a flat "key" section in the brass center that has to be aligned with the pump shaft when reinstalling. So there it is, everything is flowing fine again. Here's a link to the rebuild kit:

https://www.amazon.com/Raritan-Impe...90-aad0-24b29b656ec2&pd_rd_i=B000XBAZTW&psc=1