Saving Old Seagulls

Was breaking up a dead Anzani Pilot today and had a look at the pump . I've never had need to dismantle one before , generally they just seem to work . Why did these never take off ? For ease of maintenance they're streets ahead of impeller pumps

Yes very simple and easy to work on.

After giving it more thought I'm not sure how you could have it on F-N-R box without continuous rotation at prop