When I go to start my glow engine, the electric starter keeps spinning the prop off. I'm putting on the prop good and tight. What am I doing wrong? Thoughts?

It needs to be tighter. Use a crescent wrench, not one of those little things that you also use on your glow plug.

Also, before applying the electric starter, turn the prop clockwise (looking from in front of the plane) until you feel the compression. Don't use your fingers to do this as sometimes the engine will pop when it hits the compression. This gives your starter a running start before the prop hits any resistance.

Using a crescent wrench is a little better than the glo plug wrench but still not good enough. Use the box end (the closed end) of the exact correct size combination wrench. A 6 point is best but a 12 point will also do quite well. Also a good quality wrench, Snap On, Mac, or Craftsman will allow you to get the nut tight enough without rounding the nut. A couple drops of blue Loctite, then install and torque the nut. Using a hollow cone shaped spinner, either plastic or aluminum, will transfer the torque of the electric starter to the drive washer of the engine instead of directly to the hex nut holding your prop on. The electric starter is spinning in the direction to loosen the hex nut, sorta like an impact gun removing the lug nuts on your car but without the hex socket. I also find it difficult to use an electric starter on a plane (that would be someone else's plane because I won't set one up that way) that has no conical spinner and just the small hex prop nut that comes with the engine. I don't understand why some people do them that way. If the plane's style calls for no regular large O.D. hollow spinner and you're going to use a "spinner nut", then either a matching locking nut or a good helping of Loctite + making it really tight is a must. For 4 strokes the two OEM locking nuts is best. I have done a couple of 4 strokes with just a well tightened Loctited spinner nut but it can be risky as a 4 stroke will sometimes run backwards when you are starting them up and if the nut were to spin completely off you now have a flying nut and worst of all a spinning propeller not attached to anything. No lock nut on 4 strokes is not recommended. Also if you are using a wood prop, no matter what style spinner or spinner nut you are using, they must be retorqued after a few flights. The wood will compress and you must reclamp it down down to maintain nut tightness.

You might have flooded the engine. If it hydrolocks the starter is turning hard in the direction that unscrews the nut. Try pulling it through manually first...careful! A chicken stick is advised (but if you have a wooden prop a chicken stick and a flooded engine will break the prop; if composite prop, have at it).

For a chicken stick I use a length of about a 3/4 inch OD heater hose from the auto parts store and jam the right size dowel onto it. I always have a chicken stick in my flight box. Sometimes I just start the engine with it, and sometimes I use it to tell what the engine is doing without risking my fingers.

Jim

Are you using a spinner with a plastic backplate? If so, that's your problem. Cut a piece of open mesh plumber's sandcloth or drywall sanding sheet to make a washer to put between the prop and the backplate. That will add considerable friction there, enough to stop the prop from spinning loose.

I'm not disputing what the others are saying about this at all. Lots of people have said the same things, often from bad experiences, and I don't doubt them. Just my personal experience is that I have never had to do more than tighten the nut with about as much force as I can muster. I'm not a particularly strong guy, but I give it what I've got. I often use plastic spinners, even on four strokes up to 50 size. I have an aluminum spinner on my OS 70 FS. I was going to try a plastic spinner on that one too, but when I tightened the nut the plastic distorted, so I bought a metal spinner. Plastic spinners differ, some are tougher than others, which may account for the various experiences. My Dubro on a Saito 50 has never failed me.

I tighten nuts with a Robart wrench, and spinner nuts with a rod through the hole when there is one, or an adjustable wrench if the Robart won't fit over the nut. The Robart works for all stock prop nuts, metric or English.

The one thing that has kicked off a prop recently is when I was trying to start an unfamiliar engine. I was amazed when it kicked off the prop twice in a row, even though I had put it on tight the way I always do. That's when tried the chicken stick and got a hard bump. It was not actually hydro-locked, but it was flooded and inclined to kick back (OS 46AX). I've run a lot of Enyas and they like to be very wet, but some other engines do not. This is one that doesn't. Once I cleared the flood, the prop stayed on and I started the engine.

Jim

Is the nut bottomed out? Try using a washer

Read this thread.

http://www.rcuniverse.com/forum/begi...backwards.html

Interesting. Never knew that an engine could/would run backwards. Good to know. Ok, so with all of that being said, correct me if I am wrong. An electric starter turns counterclockwise to start the engine, but if using a chicken stick, you should flip it clockwise?

No. Some engines, especially some of the larger ones, can be started that way. But it isn't something for a beginner to fool with.

No, you flip the same direction as a starter turns. The point of the thread is that if you over prime, it is very easy to lose the prop when you use a starter. Most engines can run backward, though most do very poorly. If that happens, you can sometimes get them to run forward by blipping the throttle.

Ok, got it!

Glue two pieces of 320 sandpaper the size of your prop hub back to back. Cut out a hole the diameter of the crankshaft. Put it against the prop hub behind the spinner. Dan.

That does the same thing as the open mesh sandcloth without the gluing.

I have la 10 that likes to spin the prop off. It always seems to happen when the engine gets flooded. If your engine is flooded when the prop comes off maybe better to have is come off than have something break in the engine.