A friend gave me a used Enya .46 4C engine today for Christmas. It feels rough when I turn it over. I can't decide if it is the bearings or the gears. If I rock it back and forth gently, and keep going, it will get smooth for about 180' but when I start turning it over the roughness comes right back. It feels a little like tight gears, but it could be a bad bearing. I have no idea how many hours or the condition of the engine other than this. IT does have compression.

Should I clean it, run it, and then see how it feels? It may need to still be broken in for all I know. Or, should I just send it back to the MFG. and have them check it out and repair it as needed?

Just seeking ideas,
Thanks, and Merry Christmas,
Soj

If it has been a while since it was run last, you can take some low nitro fuel and fill the crankcase up with it. Sometimes engines that haven't been run in a while can have some oil gummed up in them. The new fuel should loosen it.

Take the backplate off, and see if there is anything noticable inside, like rusty bearings or something. You should also take a look at the camshaft and see if it is rusty or has worn teeth. The pushrods and the rocker arms for the valves could be the problem also, but not likely. I have a Saito 120 that had the same problem you are having, and although the bearings were in need of replacement, the camshaft was the problem. The teeth on it were binding against the teeth on the crankshaft. Since I didn't know that much about engines at the time, A club member fixed it for me. He just made a shim for the camcover.

Enya factory parts are EXPENSIVE. MRC (the importer) sometimes gives a break if you send the engine in rather than order parts. If you take it apart for cleaning you may as well replace the bearings. You can get good bearings at a good price from BOCA Bearings in Florida.

Hello; You describe the noise and roughness pretty well, my guess would be the rear bearing. The Enya 46 is a pretty durable engine well worth saving. Take the front case off, the crank will stay with it, then you can push and turn the crank and feel for roughness, you will also be able to see the balls turn and look for rough spots. If you decide to replace the bearing (probably), just heat the front case in an oven and push the crank out then tap the case on a piece of hardwood, and if your lucky the bearing will fall out easily. The bearing might come out when you push the crank out. You don't have to touch the cams valves or head to do this. When you re-assemble the engine just make sure you index the crank pin with the cam shaft and don't damage any gaskets if there are any. Enya engines are a little different, but their construction makes this job much easier then Saito or OS in that you don't have to disturb the cam. You might ahve noticed that you can't remove the back cover, as it's the cam chest.

Good news, I put oil in the carb and in the case and turned it over and let it sit over night. The next day it felt 90% better. I put a glow plug in it and primed it a little and it fired right up. All I need now is a throttle arm, and a plane to put it in. I have plans for a GeeBee Z by Adrian Page. I have wanted a 4 cyl. engine for it and I think this one will work great.

thanks for all the suggestions and advice.
soj

PS: LadyFlyer, I've tried for over 20 years to get my wife interested in airplanes, no go. I always think it is really cool when a woman enjoys this great hobby...:~)