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Joker Valve – Sailing – Sail Away Girl


Hello Sailors,

This past season Irish Rover needed the joker valve on the head replaced and Ross, the owner, suggested I be sure and know how to replace one of these. So I did some research to find out first of all what the heck a joker valve is and how to replace one.


Well it so happens that my July issue of Practical Sailor happened to cover not the directions for replacement, but the testing they did on several brands of joker valves made from different materials. They also did extensive testing on the impact of chemicals and lubricants on the longevity of the valve.

To start with, here’s what a joker valve looks like:




Secondly, here’s where the valve goes on a Jabsco manual head – I highlighted the joker valve in pink since this is a bit hard to see here.:


Thirdly, and the final image, is a photo of a Jabsco Manual Head.



Guess what? No one takes glamour shots of marine heads and their parts for licensed use on the web. So I must thank Defender and Jabsco for the use of these pictures.

So what did Practical Sailor conclude? Here’s my summation for you:

1. In case you were no clued in here, Jabsco was the winning Joker Valve.

This is a neoprene valve, that due to its unique design and neoprene compound, it opened wider and created less pumping and clog resistance. Please note, this valve is not resistant to propylene glycol that is typically used for winterization (see 3 below).

2. For winterization of the head, draining the system is recommended per manufacturers instructions.

Draining the system is the preferred winterization choice even though it is more labor intensive.

3.In lieu of draining, the only choice is to use propylene glycol.

NOTE propylene glycol is damaging to neoprene so never use this method with a neoprene joker valve. This is not a conclusion of Practical Sailor but my own suggestion. Since you have to lubricate the system annually any way, why not use a non neoprene joker valve for winterization, then in the Spring, come back and put the neoprene joker valve back in. Might be an easier solution than draining the system.

4. Lubricate annually with synthetic grease.

5. If you regularly add oil in the head to lubricate the system, use olive oil.

Other oils were found to cause odors and to gunk up the waste and hose walls or coat the surface of the holding tank preventing the transfer of oxygen also leading to odors.

6. Flush well.

Stale urine was found to be quite harmful to the valve and was the most harmful of all the chemicals that were tested. If there is a concern for water usage, get in the habit of giving the system one good flush everyday to make sure all the urine and other waste has cleared to the tank.

7. If you must use chemicals, use marine or RV chemicals as per manufacturer’s instructions.

8. CLR is ok to use.

This is a mild cleaner that can help with scaling control

9. Never use any cleaner containing a solvent or natural oils, and never use bleach or disinfecting cleaners.

10. never use a plunger as it can invert the valve and be damaged.

11. Install the joker valve with the slot vertical to prevent drooping and ultimately leaking.

Please note that all brands of joker valves are the same size and therefore interchangeable so you do not have to have a Jabsco head to use a Jabsco joker valve.

Now to a more savory subject…..

Don’t forget to subscribe below and get a chance to win Fabio Viviani’s new cookbook. Winner will be randomly selected from all subscribers as of January 15, 2014. Good luck!


See you on the water,

Sail Away Girl