Here's an intriguing one for the experts !

Tried some different fuel recently , a British make of high quality. It contained 18% synthetic oil to which I added my own castor [ Castrol M ] to take the lube content up to 23% in total.

What I found was , my ' modern ' engines [ Magnum 36 , Tower 40 ,  TT 36 etc ] loved it.

My ' old ' engines , including both my Enya 35's [ one a 5224 , the other a 5225 ] hated it !! They were both well run in by the way.

So we come to the old ' castor only ' arguement I suppose.

Question : Why do the newer ABC engines run fine , but the older steel liner/iron piston engines loathe this fuel please ?

If the answer is obvious please excuse my lack of technical knowledge fellas.

Much obliged as ever for any contributions ,

Robin [ ex-pat Brit in the Charente full of ex-pat Brits ]

Bob , much obliged for that .

Both my ' Old ' Enya's would run away into a two stroke at fairly low RPM with the fuel I mentioned , around 8,000 and sounded very ' harsh '.
Thanks anyway for taking the trouble to comment, much obliged.
Robin

Robin

Try running the Enyas on the fuel before adding the castor. Do this on the bench... mostly so you don't let the engine over heat .. I have had problems with mixing castor into fuel vs buying it already mixed. Adding a lot of castor didn't help me a bit either on older engines.. the old Enya engines were and are quite versatile. They came with the high compression head for team racing.. that event can and does let one know what an engine is really made of character wise.. I used to run my old Enya 35 on Dukes Fuel which I believe was only 20% oil.. so try adding just enough oil to bring it up to 20%.. you won't hurt it.. I put 300 flights on my old one as a teenager.. it is still running great today. If I remember, I went to Dukes fuel because Fox SuperFuel wasn't cutting it.. and I couldn't get K&B 100...

I was running the white plastic TF 10x6 props growing up... wood was too expensive for me.. also the venturi can be restricted quite a bit and they still run strong.

I like Sig fuel a lot.. Powermaster is excellent.. but as of late I have problems getting it.. I have to drive an hour to the only HS that carries it and the last time they didn't have any..

I am starting to get rid of all my old engines because fuel is an issue. Switching over to ones that can run on 20% oil 50/50 blend seems to be a good way to go.. IMO.. fuel is the biggest issue we face as Stunt Flyers.. we have the best of everything else..

Jim