Hi,

I just bought some 25% nitro, 16% oil to run my evolution .46 on because the guy at the hobby shop said it would work. I just wanted to get a second (or third) opinion, because someone at my flying field said I should have at least 18% oil content and I was also wondering if 25% nitro might be too high for that engine.

Thanks. I'm still pretty new at all of this.

Sounds like the guy at the shop wanted to make some extra money or clear out some 25%. Most sport engines do just fine on 5 to 15%. As far as oil content, most airplane fuels come with enough to make modern engines happy.

Thanks Chuck,

I was running 10% oil content with castor oil mixed in. A guy at the field told me I could ruin my motor on so little oil. Do you agree?

I think 10% is way too low, although there is one person on RCU that would disagree. Since you didn't say how much castor you added, it's hard to comment on the final result. The value of some extra oil is that the engine will last longer, and it will protect you from occasional lean runs.

It is says on the bottle synthetic/castor mix 80/20 or something like that. Also, will castor create black residue on your plane as opposed to clear? The guys at the field said it looked like something was wearing in the engine.

castor oil will leave residue ..can you get Coolpower or Omega fuel in 10%, 15% or 20% at your hobby shop.. if can get either one of those in either of the percentage nitro you won't have any problems

there are other fuels but those are two that i'm more familiar with

From page 5 of the Evolution manual
http://www.horizonhobby.com/ProdInfo...inesManual.pdf

Fuel
The Evolution Engine comes pre-run and adjusted from the factory. We recommend using high quality Cool Power Omega, Hangar 9® AeroBlend™ or Power Master fuels containing 10 to 15% Nitro. The Evolution Engine has been test run using these fuels. If another brand of fuel is used, it may be necessary to slightly adjust the needle valves to compensate for the differences in fuel.

-------------------------------
The cool power and omega have 17% oil according to the charts at http://www.morganfuel.com

OS will you please get on the boat ?

"OS will you please get on the boat"

Dont be so quick to think that just because these Evolution engines come "pre adjusted" from the factory, you wont have to mess with them at all. I've got two Evolutions, a .46nt and a .61nt, and I've had to readjust both the high speed and idle needles on both of them to get them to run at all out of the box. The .46 was easy to get set, even though I had to go outside the factory stops to get it right, five minutes and it was running like a top. The .61 on the other hand, has been a stone cold B***h to get set. I dont know what kind of atmospheric conditions they simulate at the factory to set these engines up, but they are not anything remotely close to real world conditions in my area. "pre-adjusted" to me just means they got it to run at the factory, and "factory run-in" just means that after they got it to run, they let it run for 5 minutes or so. They DEFINITELY do not "break in" the Evolution engines at the factory, as some on these forums have stated in the past.

I would save my money and by 10% to 15% nitro, with 16% to 18% oil content. I started out on Powermaster, and have now switched to Wildcat Premium Extra (15%). As far as the Evolution manual saying that changing fuel brands will mess up your settings, maybe, maybe not. I made the switch from Powermaster to Wildcat, using the same nitro and oil content, and didnt have to adjust anything.

Chicken,

Black residue is BAD. That's usually a sign of AL rubbing against AL. Lean runs will do that, as will a loose muffler, for example. Castor should leave a light to medium BROWN residue.

25% will work in the Evolution, but it's a waste of money in that engine, IMO.

Dr.1

What boat? R/C carbs are way too simple to adjust for every possible fuel and running condition.

stick with the 15%nitro and 18%oil,,,,it keeps the engine happy and wont break the bank. 25% if more suited for the pylon, aka high performance aircraft. If your just getting started, the difference spent could be better used for other aspects of the hobby. IMO

thunderchicken I have a OS .46AX 2-stroke. OS recommends in the manual that no less than 18% oil mixed by volume is to be used. I'm sure 16% oil would be ok. If you get worried you could always by a few litres of Klotz KL200 to mix in, but I havnt tried even though they sell it at the LHS near me.