Hard pumping head

[waughoo]

I had that problem and decided to change to a raritan superflush residential bowl head.  MUCH better pumping action, larger bowl size and the super flush has the same mounting bolt layout so it was an easy change out.

[glennd3]

Looking to replace my Jabsco head. Can anyone tell me if the Household size is really noticeable over the compact size. Never really comfortable on the compact size I have. In fact hate the size.

[Jon W]

Same here, might as well use a bucket  . I'm saving for the Raritan SuperFlush household size. Glad to hear from Alex it's a better piece of equipment and the mounting bolts match the old Jabsco.

[waughoo]

I too HATED the small size of the marine sized head.  The size of the household head is VERY noticable in use but fits VERY nicely in the space available.  The only modification I needed to make was in the hole in the bulkhead where the hose exits to the tank.  I had to oval out the hole a bit as the L fitting is a bit deeper than the 45° fitting on the jabsco.  The mounting holes of the superflush are an exact fit.  I bought mine from Marine Sanitation and the price was fantastic.  They are local to me in seattle, but their online store ships.  Do the swap.  You wont be dissappointed.

https://marinesan.com/raritan-superflush-p102-large-bowl-toilet/

[Jon W]

Good price! Did it come with the slow close toilet seat?

[waughoo]

Yes... slow close seat was included.  I can't say enough about how great this upgrade is.

[Jim Hardesty]

I'm considering replacing the Jabsco with a new Raritan.  I was happy with the original Jabsco but not with the new twist n lock.  Has anyone with a MKll installed the full size bowl?  How did it work out?
Jim

[Ron Hill]

Jim : It just occurred to me - go to an auto parts store and see if they might have a replacement "O" ring that is the same size as that large "O" ring at the bottom of the pump shaft.  Then cover it with plumbers grease (silicone based) and see if that doesn't make it easier to pump!!

An old time hardware store used to have "O" ring stock that you can cut and glue the ends - making your own "O" ring.  Another thought

A few thoughts

[Stu Jackson]

Bowl sizes are usually posted on quality "toilet" (head) websites.  I'm sure Raritan has the dimensions.  Compare how much bigger they are than the "marine" size.  You'll no doubt find them not much larger and should fit easily.  Just compare that to the multiple photos of PHIIs installed in the 101 Topics head replacement posts.

[Jim Hardesty]

Then cover it with plumbers grease (silicone based) and see if that doesn't make it easier to pump!!

I did that every spring with the original and disassembled the new "twist n lock" found it to have been lubed at the factory.  The pump handle moves easily up but on the down stroke feels like a restriction to the water flow.  Putting some pressure on the handle holding it down can feel the water flowing slowly and a sighing sound.  Pumps harder pumping the usual ####.  I did email Jabsco with my problem, haven't received a reply yet. 
Shamrock is done for the season.    So will make decision to, repair original pump or maybe hear from Jabsco with a fix or replace with Raritan possibly with larger bowl.
Thanks to all for the good information.  Will get back if Jabsco responds.
Jim

[Paulus]

Jim, would appreciate your findings.  I have the same issue on the down stroke, but only occasionally.
Thanks,
Paul

[KWKloeber]

I don't know
1) if this addresses the hard pumping issue or
2) if y'all have already tried this or
3) it applies to the model
But whenever I have a hard handle, I pump a couple ounces of mineral or baby oil thru the sink drain and 99-95/100% of the time it fixes it.  Just another idea that works for me.

[Jon W]

FWIW - Next time when hard pushing down, check that the empty bowl lever has stayed all the way to the right. Mine sometimes drifts slightly back to the left when pumping. Can't tell it's moved by sight. Pushing the lever back to the right again solves the problem.

[Roland Gendreau]

I had this problem in the spring and silicone grease solved it.  Last winter , I had put about a half gallon of leftover pink antifreeze in the head.   I suspect the antifreeze impacted the O rings in the head pump  unit.  I won't do that again.

[glennd3]

 Maine Sailor explains the difference of the types of anti freeze. The cheap one is not good for seals. I did the same as you

I had this problem in the spring and silicone grease solved it.  Last winter , I had put about a half gallon of leftover pink antifreeze in the head.   I suspect the antifreeze impacted the O rings in the head pump  unit.  I won't do that again.