Well hey there! I am thinking about getting back into flying again after a long layoff. The Sig senior kadet ARF looks good for my trainer with an O.S. .46 or Evo .46.
O.S. was a "no problems for me" engine, but I like the pipe muffler option on the Evo for a later Sig arf.
Soooo, makes the most power, and more importantly,
are there reliability problems etc. With the Evo?
Thanks in advance, Scott.

Oops, I meant who makes the most power

No answer all day, I will go out on a limb. My Evo .40 outrevs every OS that I have, FX AX FP LA SF. Even the .46s. I would guess the .46 Evo to be better. All checked with 10%, MA 10-6, and no muffler, in case mufflers were a problem. See if there are more responses now.

I wasn't going to post because I'm such a hater, but I'll bite. What the hell.. . Go for chrome. Evolution makes a nice engine and they're real ABC.

Hell, come to think of it.... I think OS and EVO are now made in the same country even!

Lol, good one there Tim. Same country. That's a knee slapper for sure.
I've bought 8 46NTs. Well, one was given to me by a guy who said his wouldn't run and he was going to toss it in the trash. I offered to take it off his hands and $20 for postage got me the engine. IMO, the NT is machined to higher tolerances and most certainly has more power. Just remember to replace the fuel tubing running from the remote needle valve to the carb. That's an easy job that only takes a minute. And, be sure you're running OS A6 glow plugs.
Here's the final test to help you decide- compare repair parts prices. The OS is going to cost you around 50-60% more every time.

Mine ran fast and since then I took off the flywheel weight. Maybe it will be even better. I have not seen too may at swap meets but will pick them up now, not that I need more motors. I don't mind made in China. It is kind of the new Made in Japan. They can stay there and work and seem to be able to get by. If they come here and get paid minimum wage, they would have a harder time. I think the quality is more up to the importers and their QC, and what they accept (and are willing to pay for) I have some Russian engines that are very very poor quality, and others that are better than anything else period. A $35 motor, and a $250 motor. Oh, the Chinese hired my son for a year. Something that no one here would do, and at work we had a few contracts with the Chinese that got us through some tough times. The U.S. pretty much abandoned us and then paid us less and less for the products.

Evolution engines are made in China or Taiwan - same difference really. OS has moved production of many or most of their engines to China as well. No knee slapping here. Dead serious. The real difference is whether you want your liner to peel or not. If not, get the Evo. It'll outlast the OS and cost half as much and probably make more power.

CHINA FTW!!

Either engine will provide plenty of power for the Kadet Senior Sport ARF.

I flew mine on a .32 sized electric, and it would perform normal sport type aerobatics.

The one thing that I liked on the new 46 NT's is the tight pinch each engine had. And no missing parts, like glow plugs.

Getting around the ban on chrome plating in Japan probably had a big role in the decision to move manufacturing too......if OS is going to use chrome like the other 99% of engine companies.

Not likely. Enya metal products is still very much in business and uses hard chrome in several of their engines. Their AAC constructed engines are fantastic. By the time an Enya is worn out, you would have worn out a dozen OS's. Enya also uses what they call ABN but is actually a form of Nikasil - they just don't call it that due to Nikasil being a trade name.

I have a couple OS engines that I had intended to get running again, but are all flaking chrome. One only has a gallon through it! I'm in the market for a couple new .46's and am done with OS. I've been reading that Evolution are decent, I've tuned a few for others at the field a time or two, but have no idea of long term. Where is a place to find Enya engines in the US?

I guess I stand alone on my vote for OS for cheap ARFs. The Evo engines like 4 stroke plugs, what do they cost nowadays? My SF and FSR OS engines haven't let me down with any liner issues being careful not to abuse them running them lean, or have I ever suffered power issues in 20 years of flying, but I turn over most engines after a few seasons than face the rebuild price. The FX I understand takes chrome liners from ASP, and not subject yourself to a crappy carb, which is what I want most, is tuning quality.
If I want "more power" I'd get a Rossi. For sport plane flying, the OS carb has the best tuning, transition of any carb I've tuned. My OS engines were made in Japan. Have no intentions of ever buying a "new" engine. Not with so many giving up glow, you can pick one up for $30-$50. For chrome, I've enjoyed the Thunder Tiger Pro, and yes, it has sport plane power. Abandon the thinking Evo, Magnum, ASP, OS, Thunder Tiger, Enya, are going to cary more than 500-800 rpm, they're not going to. Throw a 9X6 prop on a Rossi .40-.45 and get .60 like fuel consumption at 16,500 rpm and blow your ailerons clean off your ARF. The idea of trainers and low wing trainers, isn't an extra 10 mph speed, but to develop good flying skills, enjoy landings, and mild aerobatics. Jett or Rossi on the right pylon / pattern / quickie 500 plane will give you all the cheap thrills of performance, and durability of higher quality, that comes at a premium price.

engine will provide plenty of power for the Kadet Senior Sport ARF.

Hi I just picked up a used OS max 46 a few months back for $80.00 buck wow what a nice running engine! I did notice the piston seems to be a little discolored but I don't see any flaking and this engine just purrs like my other brand new AX 35 and 25 and seems to have ample power for my purpose. I had a OS XZB blue head verson one that I ran about 3 gallons of fuel through before I sold it for a new version 2 which is mounted in my car and hasn't been fired yet!
Michael Johnston

I think OS has working out the nickel plating problem at this point, but they still have their fair share of issues.

Os .55AX is same size that .46 os and is very much powerful.