A couple of questions...

Is it possible to turn the carb around on an OS 2-stroke the way you can on a 4-stroke?

I bought another Tower Trainer to replace my crashed one and am looking to place the engine sideways on this one so that the muffler is on the bottom. This will make the engine just past 90 degrees... Say around 100 degrees from upright. Am I setting myself up for problems?

Not sure what you mean by "turning the carb", but you can turn the engine sideways without any problems for the engine itself, it will run fine. I have several O.S. and other two strokes mounted like this. The problem you might have is getting the throttle push rod where you need it. You will have to route around or under the fuel tank to come thru the engine mount and fire wall and meet up with the linkage.

ive done it before.....its kind of awkward on some carbs having the fuel nipple point towards the carb, and adjusting the needle valve feels a bit different too. some needle valve also have a rotate able nipple makes it a bit easier


he means turning rotating the carb horizontally 180 deg.

Ok, I haven't had to do that myself, but I can see where on some planes, rotating the carb might make it easier to get the linkage close to the same place as it was.

That's the point. If I can tun the carb around I will not have to move the throttle pushrod. This engine has a remote needle valve so the fuel line to the carb will just go around the other side of the engine.

This installation will be a little more down than sideways. Like around 100 degrees. I had heard of problems with inverted 2 strokes. While this will not be inverted, it won't be 90 degrees either. Just wondering if anyone has experience good or bad?

Typically on some warbirds engine are mounted at 135 degrees to center the muffler under the center of the fuselage and of course ninety degrees works fine on many airplanes and is my favored mounting orientations.

Both work well and neither have as severe fuel tank/spraybar relationship problems or the syphoning problems of an inverted setup.

However the way it is done is to put the throttle pushrod where it needs to be and in the vast majority of installation is along the bottom right side of the nose section. If you are going to change the engine orientation then that is where you position the pushrod.

You never said what the engine is and now on some it will not work. For example if it is a LA series engine then that bleeder hole needs to be facing forward directly into the propwash.

The thottle postion on any engine dictates where you put the pushrod not the other way around.

John

Not sure if all LA .40's are the same, but on mine, the little black plastic fuel inlet nipple on the side of the carb can be rotated. It appears to be pressed in...not threaded. The way I found that out is because I got it as a gift...but the remote needle was missing. I wanted to see if I could install a new N.V. right in the carb body...but nope.

So...if yours is the same as mine...you could turn the carb 180 degrees and then rotate the fuel nipple so it still points rearward.

Thanks for the replies. I tried it on the engine and the carb turns around fine but the remote needle bracket interferes with the engine mount when moved to that side. At this point you are right... It will be much easier to move the pushrod than mess around with moving the carb.

I'm glad to hear that you have had good luck with two strokes rotated past 90 degrees. I was thinking I might have starting/idling problems. I am looking forward to having the exhaust exit under the plane so I won't have to clean as much gunk off the wing and side of the fuselage! I'll be cutting the cheeks off and converting to conventional gear to accommodate this arrangement.

As long as the engine is above the fuel tank you shouldn't have any starting/ idiling problems other than over priming.

I've mounted O.S. .40's upright, sideways and upsidedown and they all ran fantastic. Connecting a tube onto the muffler and running it to the trailing edge of the wing will help with keeping fuel to a min. When flying rc planes of any type, I push them well beyound what they are designed for and fuel gets everywhere, but if you fly somewhat normal you shouldn't have to much to wipe off, goodluck.

Ibelieve the last five glow models Ihave built/assembled had the muffler low and centered. Keeps the exhaust off the airframe and the weight of the muffler tucked on the centerline.