Johnson pump

[Marty Levenson]

I have had the Indigo fresh water cooling system for over three years, and it has been great. I installed the ballast resistor that Tom sells to give the electric pump a gentle ride. Even so, I am starting to think about carrying a spare electric pump because sooner or later.....

I am wondering if there is a source for the pump in Canada. The exchange rate is a killer, plus taxes at the border = very costly to import. When I download the manual from the Indigo site I see it covers two Johnson Pumps:CM30P7-1 Centrifugal Pump as well as the CM10P7-1. Does either one work? Or is there a cheaper substitute?

Thank you!

[joe_db]

Johnson Pump 3/4 in. CM30P7-1 is the one you want. It is the higher flow 3/4" version. The forum experience with cheaper Fleabay substitutes was not good.
A couple of thoughts:
Just having it is not all that helpful, it needs to be plumbed and wired. Swapping pumps, dealing with bleeding the engine, and getting coolant all over the place would not be fun underway.

Check the pump voltage with the resistor. If you lower the pump voltage too much you will gain 10 or 20 degrees running temperature. I would not go below 12, but YMMV.
The switch here is for the second pump, the first one switches on and off with the ignition.

[Marty Levenson]

Nice set-up!

Thanks for clarifying which pump I want.

Yes, I will plumb it in as shown on the Indigo site. Plan to carry it this summer, and install it next winter. Might be simpler to temporarily reorganize the hoses to RWC if the pump fails.

I will double check my resistance, but water temp has been solid at 180.

[joe_db]

If my pump fails I am 10 seconds away from being underway again - I just hit the switch. If you are going to bother buying it, I would strongly suggest plumbing it in.
IMHO

[ndutton]

I agree with Joe - and something you said. I felt the same way, have a spare Johnson pump in case the installed one failed so I bought the spare. Then I started looking at what it would take to change the pump on the fly, refill with antifreeze and purge air. YIKES!

In the event of pump failure and the need for a get-home measure, it became obvious reverting back to RWC was exponentially easier and did not require purging so my Plan B went that direction. What to do with the extra pump then? It wasn't doing me any good on the shelf so I installed it and now run two electric pumps in series. Both will have to fail before I need my Plan B and if they do I have a short length of 5/8" hose pre-made to revert back. Adding the second pump added electrical load to the ignition system too so voltage measurements were taken to reassess voltage drop. Turned out the added pump bumped my voltage drop a little above 5% so I increased the purple wiring in my engine harness from 12 gauge to 10 gauge, remeasured (now under 3%) and called it good.