Nathan,
did you check the condition of the piston sleeve? The first production run (or two) of the 'ABC' (really ABN) OS longstrokes had very poorly plated sleeves. OS would replace the piston/sleeve for free if it was obviously a low time engine (and no 'bluing' from lean runs). I sent 2 back as did quite a few other pilots (including Ivan Kristensen who ran the OS RF-ABC pump briefly). Plugs and bearings would go 'bad' very quickly with all the nickle plating floating around inside the engine.
I hope new bearings solve your problem.
-Will

Will, you're not kidding about those nickel plated sleeves. This one if from an early (30mm bearing) SF .61. This particular engine is getting a ringed piston/liner replacement with a new ring and new bearings. That should give it new life.

Nathan, does your sleeve look anything like this?

David

Hi David:
I just took an old OS 61 FSR out of my Utter Chaos that was giving me trouble and I think we have the same sleeve. I have also rebuilt with new brgs and a ringed piston and liner.
It always amazed me how OS could make such a good fit of piston and sleeve and have good running motors out of the box but the plating NEVER came off the Enya's and others that took forever to break in.

Peace

Mark O

Sniff_Sniff [sm=cry_smile.gif]

Anyone got a spare Hanno Piston/Liner???

No, I don't mind any engine links being posted. The bearings are ordered, and I took a look at the sleeve. It's nothing like the picture that was posted, but it has a few small "spots" near TDC that I didn't notice when taking it apart.

PS That engine you linked was gorgeous!!!!

PM Sent...