Hi Pat,

I didn't know that about 3W oil. Separating after sitting is not good. Frankly I've used all that oil up. It's expensive and not locally available so I don't use it any longer. I use Belray MC1 for everything, including my KTM300 motorcycle. Very fine oil that has given me no cause for concern. I realize my motorcycle experience does not translate, but I've burned about 1000 gals of gas with Belray MC1 in my 93 YZ250. I never had a failure of any kind. But of course this was water cooled.

In my models I have tried to learn from others. I played around a bit with the high ratio oils and got to clean out cruelly hard deposits all the while marveling at the lack of oil residue on my plane. Now I buy Belray MC1 at my motorcycle shop and have one oil for all my engines, very light carbon (if any at all), a little residue on my plane (running 40-1) and piece of mind. I regularly run a BME44, BME 102, DA50, Evolution 26gt2, Zenoah 26, and 3W80xi.

For me, Penzoil aircooled provided nearly the same results but was not available locally. So I don't use it. That's it, no better reason.

Thank you for all the information you've shared in these forums (RC Bugman too) and the heads up on 3W oil.