Replacing Johnson bilge pump with Rule pump

[scross]

My 2009 RT-25 Classic has two Johnson 750 GPH bilge pumps. Last season the aft bilge pump had engine oil go through it when the turbo oil hose was being replaced in the shop.
My existing Johnson pump looks similar to this:
Johnson Pump Cartridge Combo Bilge Pump 750GPH, 12V https://www.amazon.com/dp/B002IV8ID0/re ... LFbDEXCV4A

This season automatic pumping function stopped working. Pump works in manual operation using switch on DC panel. 24/7 fuse is fine. Tried flushing the pump with soapy water without improvement.

So I’m thinking of replacing the 11 year old Johnson pump with a Rule 20SA pump. The Rule 20SA is rated just a bit higher at 800 GPH. I believe the Johnson and Rule both use the same sized 3/4” drainage hose. Also, I believe the Johnson pump uses an internal check valve that the Rule does not so I will need to add a check valve into the hose with the Rule.

Looking for confirmation on hose sizes and the need to add a check valve if I go with the Rule 20SA.

 

[Hamster]

My 27SA failed after two years. Rule is sending a replacement. But, reviews are not great on the automatic sensing. Pump otherwise works fine. I’ll give it one more try but will switch to float if fails again.

 

[ALICE J]

You might try draining the bilge by opening the garboard plug drawing the contents, maybe making a soapy solution with a long handle brush, drain. I then took an oil solvent maybe acetone and throughly wipe the contact buttons on the water level sensor. That sensor seems to attract any kind of oil, so clean, clean, clean!

 

[CAPTCRUNCH]

Has the world given up on low-tech float switches? That's where I'm headed. That, and mounting pump/switch on some kind of removable stalk so I can pull them up from the bilge instead of standing on my head wishing my arms were longer.

 

[YukonRon]

Our 2013 R25sc has the same Johnson pumps. Our aft pump has a check valve in the outlet line a couple feet up the hose, just above where the seacock is. My check valve has had some issues with plugging up lately but seems to work now after blowing the water through by mouth a few times. Time to disassemble and clean it. So, I don't think these pumps have built in check valves.
The forward pump, if I'm correct, doesn't need a check valve because the small amount of water that runs back down will go to the lower part of the bilge and not cause the pump to cycle.
Yes, these are finicky and the circles on the actuator need to stay squeaky clean. I'm also looking for a replacement that is more reliable and the largest volume I can fit.