I was wondering if AA Castor from the drug store could be used in a pinch. I want to break in a new 4-stroke and had ordered a pint of castor to add to my 16% fuel (adding 6 oz to a gallon not a whole pint) but was sent Synthetic by mistake. Anyway, I am really eager to get this engine running but don't want to damage it in the process. I know the drug store stuff has not been de-gummed but it would only be for break-in. Any opinions would be greatly appreciated.

I don't know what engine you are referring to, but most four stroke manufacturers recommend synthetic oil to prevent gumming/sticking valves. That said, it probably wouldn't hurt to use a blend for your break-in only. The medicinal spec castor is usually not recommended. Go with a good brand of commerical like Klotz. I have a YS .91 AC which I run YS blend 20/20 which is synthetic. You will find that most four-strokes require more nitro (15-20%) to run properly due to the time between compression strokes. You also need to use an O.S. type "F" or YS four stroke plug or I assure the engine will NOT run at less than 1/2 throttle.

Hope this helps!

G~

There is absolutely nothing wrong with using regualar good quality fuel for engine break in. It does not make sense to use one fuel for break in and then operate the engine for the next five years on whatever is available.

Ed S

I've used drug store castor oil with methynol as a fuel and I never saw any extra gum or carbon in the engine. That was 35 years ago. I still have the engines and there's no carbon in them even now. I'm sure it would be OK in a pinch.

However, a little extra of that synthetic will work fine in your engine too. You already have it. Just go ahead and use it as if it were the castor until it's gone. Don't bother with trying to get the drug store castor oil unless you just want to use it.

Castor content is recomended for ringed engines but most people in my area buy whatever fuel the hobby shop has and it sometimes may be a castor blend and it may be all synthetic. Omega heli fuel has extra oil in it. (22% total all synthetic) whereas regular 10-15% Omega has a castor-synthetic blend (somewhere around 16% total). Around here, most of the other brands are just synthetic with no castor.

I personally like the idea of a little castor oil content (but not all castor) for my kind of flying.

Enjoy,

Jim

'Medicinal' castor is TOO filtered to lubricate properly. There is NOTHING wrong with using 'Baker's AA' castor for the 'first few runs' in order to break in any glow engine. Most engine manufacturers advise to switch to/use a 50/50 castor/synth mix, or less castor, for use after break-in.

It's YOUR engine, treat it how you want to...it will either last practically forever or FAIL prematurely...depending on how you 'run' it.

Not sure but I think if it is AA castor it is good for our fuel. I think the only differance in drug store castor is that it has been tested to be safe for consumption, no poison.

The engine is a magnum 61RFS; they call for 20% percent castor only for break in. I have downloaded the instructions for OS, Saito, Enya and YS and it amazes me that all of these manufacturers differ on break in oil content and procedure, who is right and who is wrong. I know that the castor/synthetic argument has 1000 different sides to it but I wanted to follow as closely as possible the recommendations of the manufacturer.

I suggested what to do.

I would take years of experience over different instructions on books or manuals any time.

Ed S

I have two Magnum 61's, a 65, a 91, and a 120 and they were all broken in with Omega 10% nitro fuel and they all seem fine to me.

Enjoy,

Jim

All:

Check this thred:

http://www.rcuniverse.com/forum/m_18...tm.htm#1856255

Bill.