I have a small Rule (500GPH) auto bilge pump under my engine to remove any rain water or minor flows from the stern gland. It isn't an emergency pump, I have two good manual pumps for that.
The Rule pump often gets an air lock or something similar and runs but won't pump water. If I put water in the bilge and then turn it on its side it will start sucking and pumps very well. After it has pumped out and stopped, if I put water in the bilge within a very short time it will restart and pump normally. Usually, but not always, it won't pump if it has been some time since it last went.
The electrical side works fine, it just doesn't pump unless the air lock is cleared when it pumps fine, plenty of flow.
It only has about 1 metre rise and about 3 metre of hose to the outlet in the cockpit drains. I installed a non-return valve to keep the hose charged but no change.
I can't fit a bigger pump (which it doesn't need) due to hose size limitations where it passes through a number of not easily accessed bulkheads in the bilge.
Any ideas on why it air locks and what I can do about it?
Thanks
John

Could be a faulty float switch. I had an intermittent problem with a Rule setup and located the problem in the float switch. It is a sealed unit (costs about $60) but I cut it open anyway. The small spring inside was made of crappy steel (not stainless) and had rusted through. It was only 2 years old and just out of "warranty". Whitworths didn't want to know about it. I won't be buying Rule again.

Rule submersibles are good value but I have broken a few over the years. Usual failure is the impeller, it eventually just slips on the ss shaft. Impeller picks up a bit of rubbish and jams in place. The domed ss screen that fits inside the lower case is a good investment. The 360's and 500 are cheap enough to buy and just throw away when they play up.

I would not bother with pumps with built in float switches. The only bilge switch worth buying is the Water Witch, cat No 84771 for $80 at Whitworths. This is the only switch that lasts in the bilges of trawlers.
An other alternative is an automatic washing machine water level switch mounted up under the deck with the switch being made with air pressure up a rubber hose from a suitable air chamber in the bilge water.
If you wish to keep buying the traditional float switches use an automotive relay to switch on the pump, this extends the life.

I would like your input as to what you think is the best solution to my bilge pump issue.

I have a 361 Beneteau Clipper, currently have a electric and manual bilge pump but not auto. Have had advice as to what would be best practice but the problem is that the Beneateau does not have a descent well to mount a Rule type pump in. I was considering putting an auto float mechanism onto the current electric pump that is Electrically/manually operated to make it auto, the electrician tells me that I would not be able to operate it manually if I was to do so, is he taking the piss, is he trying to take an easy way out or is he correct. I am no expert on this type of issue but would like to do a little "Due Diligence" prior to making up my mind as to the best practice.
To sit a Rule type bilge pump into the bottom of the hul (not the tiny well)l would require at least and inch or 2 of water to be there at all times before the switch would kick in, I look forward to your replies.

In advance thank you for your input.

Hi Ramoana

Thank you for your input, Have checked out the product and it looks just the ticket.

Cheers.

With electric bilge pumps I wire them up with a three way switch.

On, Off or Auto (float switch) and regularly check the float switch for correct operation.

If the float switch is too deep in the keel to get at by hand conveniently, use a straightened out wire coat hanger.

God bless the man who invented those things. It had to be a man. Right??

Thank you Cisco

The coat hanger thing, yes it was a man.

Albert J. Parkhouse