A tale of three pumps

Shurflo_20881. SHURFlo 2088-422

  • 3.5 GPM open flow, 45 PSI Demand Switch
  • Self priming up to 12 feet
  • Can run dry without damage
  • One way check valve prevents reverse flow

The first pump died after 15 seasons. It sounded like a jack-hammer but was a reliable crew member on our boat,  sort of like Relic on The Beachcombers. Part of my bedtime ritual was turning the breaker off so as not to be awoken but sporadic bursts of pump.

This pump was made in the USA in 1999 and judging by the date, I’d say it was the original freshwater pump.  It started weeping at the end of last (2014) season and I ignored it. At the end of this season, shortly after finishing out trip to the 1000 Islands, it quit (almost exactly like the fridge did last year). Upon inspection the inner sealed-bearing failed and flooded the electric motor. Rust-brown water trickled out of the motor case, it was done.

2. Jabsco/Xylem SensorMax VSD

3175X_SENSOR_MAX_GRP.jpgThe second pump is a New Old Stock (NOS) unit that came with the boat, shiny and new in the original box.  It features a fancy new fangled pressure sensor that won’t shut the pump off.  I fitted a larger 15amp breaker as specified,  added the larger strainer, fiddled with the sensor but couldn’t get it to shut off.

The box has a $379 price sticker on it and I took it to my local chandler, who most graciously tried to send it back to the distributor  (alongside another even bigger version of  the SensorMax with the same problem) but no dice. Age and lack of receipt means no support, thanks for nothing Jabsco . I’m glad I wasn’t counting on it as a spare.

The advantage of the SensorMax series is increased GPM and pressure as well as having circuitry to vary the motor speed to increase the pressure in the event that two taps are on at the same time (?!). This seems like a good idea, and I can get behind the idea of a hot blasting shower, but on a boat, one is usually trying to preserve water, not blow through it as fast as possible.  (On a side note, the bathroom shower wasn’t used once last summer!)

3. SHURflo Revolution 4008-101-E65 3.0


  • 3 Gallons per Minute
  • Self-Priming 55 PSI
  • Internal Bypass-Low Cycling & Quiet Operation
  • Dry primes to 6 vertical feet
  • Thermally Protected and can run dry without damage.
  • Built-In Check Valve
  • 4 Independent Chambers
  • Mounts in any position
  • 2 Year Warranty

The third, and currently installed pump,  is ShurFlo’s newest version of their most popular RV pump.  I chose the RV pump over the “marine grade” SHURFLO AQUA King™ II as it features the same pump mechanism and motor  for less than half the price.  I don’t need the marine features as the pump is mounted in a dry locaton under in the midship lockers. At CAD $129 tax-in,  delivered to my door, it seems like the best way to go.

AQUA King™ II has the same specs with the addition of :

  • Ignition Protected, CE
  • Sealed Motor
  • Corrosion Resistant Electro Coated Motor (um – you mean paint?!)

May 2016 -while waiting for the crane to get a new starter installed I hooked up the new pump. I would say it is 50% quieter holds pressure better and cycles. I think it holds a higher pressure as the water runs for a fair bit before it kicks in. The whole mounting bracket is rubber, no doubt contributing to the reduced noise. My only quibble is once I got used to the easy quick snap fittings, going back to the screw on fittings seems crude.

Back to pump #1.

Pump #1 one has been resurrected, lets call him Old Faithful. A few squirts of oil, a little elbow grease with a scotchbrite pad on the magnets and rotor and the motor runs.

I’ve ordered a new sealed bearing for a mere $5 (tax-in,shipped). I pushed out the bearing insert in a vice. It will be nice top have a functioning back up pump, and satisfying that it could be salvaged for $5.

Leaky sealed bearing with insert.

6203Z_BearingI’ve read suggestions that de-pressurizing the water system will prolong pump life by removing pressure on the sealed bearings.

Dec 24th:
New bearing arrived and it is double shielded 6203ZZ (the extra Z) , but that really doesn’t matter as the bearings would rust if the wet side failed first, but at least it would save the motor a little longer. Here is a link to help you decode bearing numbers. http://www.gizmology.net/bearings.htm I’ll use the freezer/toaster-oven technique for putting the insert back in the bearing. Normally I would heat just the inner race but as the bearing is sealed I was curious as to how hot I should go when heating the whole bearing.

“Heat mounting is a very good way to mount bearings, particularly shielded bearings, if you don’t have a press. This process will not work for bearings sealed with rubber or rubber-like materials. Shield bearing have metal covers that enclose the sides of the bearing, and thus have nothing to melt.”

“Normally a bearing temperature of 150°F above shaft temperature provides sufficient expansion for mounting. Never heat a bearing to a temperature higher than 250°F as this is normally the heat stabilization temperature of the bearing steel. For a sealed and greased bearing, you have to take into account the temperature limit for the grease and seal material. Most multi purpose greases used in sealed bearings can handle up to around 230°F and the general Nitrile rubber seals used on sealed bearings can also handle up to around 230°F, but some type of special seal materials like polyurethane can only handle around 180°F.”

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