Plastimo Manual bilge pump

[ebb]

I know somebody here has installed one of these in their cockpit.
I just got one from Defender. Haven't mounted it.
But have tested its action.

You pull the sliding handle up and pull the lid away from its closed position.
Inside the pump has a large rubber diaphragm. Pumping happens by moving the lid in and out with the handle.

My air 'test' out of the box seems not ot produce a big enough stroke to get the number of gallons it promises. To close the pump requires a strong push against something inside the diaphragm. I'm thinking the hard-to-close aspect is to keep your knuckles from getting crunched on the bulkhead if it was allowed to close when stroking. But the safety feature seems too far out from closed - and it seems to rob the pumping action of a full stroke as it really pulls against the rubber of the diaphragm.

If I really got into desparate water removal the rubber would be really stressed and either pull out or break.

Anybody used this pump?
I have the 1038 1 1/2" hose model.
Haven't found anybody talking about this French hand pump.
Defender evidently doesn't stock spares like the diaphragm.
The cover is listed as a spare part in the manual. So I'm wondering if they also become a casualty with frantic pumping.

Has anybilgepumper found anything odd about the pumping action of this BOMBA DE ACHIQUE?