Evolution engine
 

http://www.rcuniverse.com/forum/atta...mentid=2135095I just got this old engine from a club member and I was wondering what is the black item at the front of the engine? I was taking it apart to clean it since it's pretty gummed up and replace the bearings but thought I better wait until I find out how it comes off. Is it worth spending a few bucks for bearings? Thanks for any help you can offer.

that's a evo 46 "training" engine, that black thing is a "flywheel" it helps with starting. it can be taken off, but I can't remember how I took mine off

I was thinking that when I noticed the drill points around the circumference. For balance no doubt. Thanks for your help!

IMHO I would not spend the money to replace anything on that engine. Evo's are finicky running engines at best

That's what I was thinking! I guess I wasted a buck on the club raffle. Thanks!

Those trainer engines were actually ok most of the time. Everything else that Evolution made during that era was junk, but the "PTS" engines were usually reliable. It shouldn't need new bearings though unless it was stored wrong. If it's gummy, just soak it in fuel for a few days and work the crank back and forth every day until it's loose. You may need to clean the needle valve and spraybar as well.

i'm using mine as a paper weight, does a beautiful job of holding instructions open. but seriously, it was a good engine for a awhile but like most of them the air mixture screw has issuses

Maybe I'll get it running just to see if it will then maybe add it to a display I have of old engines. Thanks for replying!

I'll double your money if you want to sell.

Seriously, I have one that I got in a buy out. Just kind of ignored it for a long time until one day I was bored and decided to get it running. It started right up and ran quite well. I have had it on several planes and it has performed flawlessly. It is on a Sig Somethin' Extra right now and I am well pleased with the performance of the plane.

You need to get rid of the flywheel and the needle valve limiter (the blue ring around the needle valve). Chances are pretty good that you will be pleasantly surprised.
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I'll keep it and get it going. I thought the bearings were bad since at TDC I can feel like a flat spot. Maybe it's just that gummed up in the bearings? I took the rear cover off and it is pretty gummy. Thanks all!

I have the evo trainer power system and like it a lot. I actually crashed the nexstar it was on, I put it on the bench and it fired right up. My engine came with a flywheel and prop driver and my flywheel comes off very easily. I may have gotten a later model????

The Evolution PTS engines are pretty good once you do a few minor things to them.

1 - Remove the limiter "Pin" and throw it away!
2 - Loosen the grub screw on the blue anodized limiter and pull it out slightly ( with it still in place it will prevent the needle from moving in )
3 - Remove the clip on the HS needle, squeeze things a bit to make it clamp tighter and so the clip holds better against the detents.
4 - Put the clip back on and put a grommet around the clip and needle to prevent the needle from "walking" in flight.

The major problems with the PTS engine involve the limiter, which in turn forces you to tune the engine poorly OR that once the engine IS tuned the needles come loose and move in flight. The above minor mods fix this.

BTW: There is no need to remove the flywheel. It helps smooth out the idle speed a lot, but unfortunately Evolution let this result in poor out of box tunings.

Thanks for the tips opjose!

That's very good advice. I did those things to my engine too.