After about 10 years I decided that it was time to get back into the hobby again. I have a trainer plane that I bought from a friend. Well, it sat for the length of time that I put above. When I tried to start it, it wouldn't. I never heard of an engine suffering from dry rot, but I guess there is a first time for everything. So apart came the engine, cleaned and re-assembled. Still no go. Replace the tank, fuel lines, glow plug, and still no go. Browsing the forums, I got some ideas but nothing worked. Since I have no docmentation on this particular engine, I was mostly guessing. Then I tried something rather odd. I reversed the connectors on my starter, tried again and it ran. So question #1 is, as you are facing the prop, is it supposed to turn clockwise or counterclockwise?

Question #2, if the answer to #1 is clockwise, how do you keep the prop on? It keeps unscrewing itself as the engine runs.

I hope someone can help me with this as I would really like to fly again.........

Thanks..

all my engines go counter clockwise. ( Standing in front of the plane)

They do sometimes start backwards though.

What kind of engine is it?

Hmmm... My first guess is that the engine is flooded. That would tend to allow it to run backward. Are you priming the engine with fuel? If so, how much? And how is your needle valve set?

The engine is a ENYA 19 X. Yeah it is a small one but it *used* to fly the plane.

I am not priming the engine, and the needle valve is set 1 to 1 1/2 turns out from the fully close position. Any farther out and it starts spitting out fuel from the carb. (When trying to start from the counter clockwise position.)

I actually had it running in the clockwise position, before the prop flew across the garage. I can barely get the engine to 'pop' when I try the counter clockwise position, and it surely won't run.

The only reason I even tried the clockwise rotation was I was reading some documentation for my helicopter engine and it states that the starter motor should run in a clockwise position.

dmac, an engine will run in either direction and if run clockwise long enough it'll unscrew the prop. One question did you put a new glow plug in?

Yes, that was one of the many things I tried. (New glow plug)

So an engine will run either way, clockwise or counter clockwise. So is there a correct direction or is it which ever way the prop won't unscrew during run time?

A prop has to turn counter clockwise as you look at the front of it. If the prop wash is blowing foward your plane will go backwards.

Then I guess I am back to square 1. I can't get the engine to run counter clockwise.

I am defininitely no expert but is it completely unreasonable to run a 1:1 gearbox so that the prop direction is reversed? I've never heard of one being used on a gas engine but it might solve your problem if you can make it work.

Modern engines may idle either way, but they won't run well backwards. In fact, many times, if my engines start backwards, giving them more gas causes them to reverse direction. Which gives me an idea...

Is it possible you reassembled the engine wrong somewhere? The direction the engine runs well is based on its timing. Since there are no valves, the timing is dependent on the physical configuration of the ports (the various exhaust and intake openings). I'm no expert, and I'm really guessing here, but it seems if you put some of the parts together wrong, you could have a backwards running engine. For example, if you put the cylinder on so the muffler was on the other side (but I'm sure you didn't do that!)

I was thinking that but it didn't make sense. I will take it apart and see try to reverse the piston. By this I mean I will disconnect it from the crank and turn in then hook it back to the crank.

I will post tomorrow after I see if I can get it to work. It's out of the plane again anyway......

I've never had one, but I've heard stories about engines that can be taken apart and the direction of rotation reversed. You'll know if yours is one of these if you can take the back-plate of the engine casing, and swap it with the assembly containing the carb, shaft etc.. If the casing is one piece from thrust washer to backplate (like most) then you obviously can't reverse it.

FYI, I have a K&B .25 that ran once in 1980, and sat in my garage until 2001. It ran pretty well for a season, but finally gave up the ghost a few months back.

The only engines that can be made to run in reverse (clockwise from the front) are those with a removeable front end (which isn't what the Enya 19X has). The front end has to be turned 90 degrees so the carb lays over on the exhaust side.

But because this can't be done on the Enya then all I can think of is that maybe the liner was fitted back to front so that the exhaust port is now on the transfer side. It's easy to check..the exhaust port is the one with it's top edge closest to the top of the liner (in other words it's the port that opens first when the piston's coming down). I don't know if these liners are pinned which would make it impossible to put in the wrong way.

dmac852...unless you've removed the piston from the rod in your teardown it can only go in one way. Look at the rod bushing and you'll see that one end has a small chamfer in the bush. This is the end that has to slide on the crank pin so that the chamfer is against the crank web. The chamfer gives a clearance for the tiny radius machined on the crankpin/crank web.

I never removed the liner. Is it possible it moved?

My Thunder Tiger .61 will run backwards, quite well. No, the plane will not run backwards. If started backwards, it will ussually spit on idle, but will spool all the way up, and will even have power to take off and fly.

Don't ask me how i discovered this. Most of you old timers can probably figure it out. Don't make me explain, i have served my pennance.

Since you dis-assembled the thing, who knows? this engine definitely is meant to run counterclockwise as viewed from the prop shaft.

yes, a regular prop when spun backwards still screws.... mine is 11 x 7.5

i dont have the answers, just the experiences.

Steve-o

Any farther out and it starts spitting fuel from the carb... a definite sign of flooding or positive pressure..

This, to me sounds like the engine is flooded, it runs until it leans out from running backwards, then it gets so lean that it backfires, kicking the prop off.

dmac, try this... Put your finger over the carb intake and turn the prop counter clockwise (looking from the front). Do you feel your finger being sucked into the carb, or do you feel pressure?

If you feel pressure, somethings not right, stop there and let us know. If you feel suction, close the needle valve all the way, then pour a few drops of fuel into the carb and try cranking it up. if all is well, it should start for a few seconds until it burns off the fuel you primed it with. Then crack the needle valve open a bit and repete the process until it keeps running.

Have you tried spinning the motor counter clockwise without the glow plug installed? Just to see if it will turn in that direction.

1st, I can't thank you guys, and gals if there are any, enough for your help. As odd as this sounds, the engine runs clockwise. I looked at a propeller that I had laying around, and for it to work correctly, it has to turn clockwise for the correct air flow. I looked at the one I had on the plane and it is the same way. Unless the wording on the propeller doesn't face the front. I sealed everything, and gave it a go this morning.

1st attempt was counter clockwise. Big suprise, it was a no go. RC_Sport stated that the air would blow in the wrong direction if it was going backwards. This is what it was doing.

2nd attempt, reverse the starter motor wires at the control panel and try clockwise. It worked. I didn't have the wing on but I was *driving* it around the yard. The prop stayed on too. It kept cutting out at high speeds, but this should just be a needle valve setting that needs to be played with. Now I need to put it fully back together and get it ready to run.

Again, I can't thank you enough.

Keep on flying!!!!!!

Good deal! You got her running. Just please do yourself a favor and use a jamnut on the prop. This way the prop won't become a projectile so easily.

Where are you going to get reverse pitch props? If I am not mistaken Enyas are weird. On most of them the rotation can be reversed. Don't ask me how though. I am looking at a picture of a .19. There is no backplate. Everything goes in from the front. Weird.

Where did you find the pic? I couldn't find anything on that engine.

werent there engines that ran "backwards" to be used on twins?

I think OS had a run of these (discontinued?) maybe enya did to.

Which way do the clocks run in your part of the world???

Heys Guys is it possible this a motor designed to be run backwards in say a ducted fan or something?

Time for a back-to-basics question...

When you say it runs clockwise and the prop pushes in the right direction, is that clockwise from the engines point of view (same as the pilot's point of view -- looking forward), or is it from your point of view facing the engine?

Normal operation is described as counterclockwise -- but that's from the your point of view looking into the face of the plane, and that requires a starter that turns clockwise from your point of view when you're looking into its face. So we could all be right here (or wrong... )

If you are standing in front of the plane, and the propeller is coming at you, it is spinning clockwise. Now if I was an actual pilot, sitting in the cockpit, it would be counter clockwise. I still don't get it but it runs. Well, other than the cut out at high speed. Which is one of the reasons it isn't allowed off the ground yet.