Hi Bax,

Thank you for the excellent information that you provide in this forum. I've found that many of my questions have been answered in the past without writing and when I have written your answers are always prompt, accurate and very helpful - so thank you!!

My current issue is with an 61-RF that I received with a fairly aged pattern plane just a couple of weeks ago. I ran it up in and found that it ran well in the air on a 12x8 (as you have suggested in other forums) but it did not idle well. The key issue here is air bubble buildup in the tubing that runs from the pump into the carb (the 'in' line not the 'out' line), there is no air in the tubing that runs from the tank to the pump. I have replace the tubing but still find the same symptom. The bubbles are still there at high revs but the engine keeps running for the most part.

I worked through the issue with a very experienced pattern flyer who has owned one of these engines and several Hanno's to boot. His advice was that the diaphragm in the pump is holed and that the problem will steadily get worse. He suggested that I send the engine back to OS via the local importer (Australia) as the pump is not servicable locally. I called the importer who advised that the engine was too old, OS probably don't have the parts and I should just go buy another engine; as you could imagine I wasn't exactly delighted with this guy's views.

Are you able to advise anyway that I can get this engine repaired please?

All the very best, Simon

O.S. has discontinued the pumps from the SF/RF series and the Hanno series of engines. You may be able to locate one through the RCU Marketplace or other methods. We'd not know if O.S. would have any still. Service was done only by the O.S. factory, and they remanufactured the pumps. We most certainly don't have any more of them in North America.

Thanks Bax, appreciate you trying to help me out on this.
All the best, Simon