rrengineer

My Feedback: (3)

I have owned and used Cox engines of all sizes since the 60s. I should know what I am doing by now. I have five Cox .010s that have sat for several years in a box. I cannot get them to run. All but one will start real strong on the prime and the stop abruptly. One of the engines is the later white aluminum and black plastic. That one was new in the box running perfectly when I put it away about two years ago. I tested my starting battery and got 1.4 volts. The fuel is 25% nitro with all castor oil. I initially thought castor oil residue was blocking the holes in the intake venturi, so I removed them and cleaned the three holes in the groove with a small wire. One of them ran out a tank. but at reduced power. The rest did as before with a roaring start and an immediate abrupt stop. What am I missing here?

DeviousDave

The one that starts with good power on the prime and abruptly stops most likely has plugged fuel passages on the intake venturi. If it runs longer than a 3 or 4 seconds, it is getting some fuel and I would suspect an air leak.

The ones that don't make good power are probably suffering from varnished cylinders-this was especially problematic with .010s. Someone made a cylinder brush (Davis Diesel?) to correct this but I haven't seen one advertised in 20 years.

The starting regimen for an .010 is:

open needle 5 turns

draw fuel up to the fuel line nipple on the venturi but DO NOT ALLOW ANY FUEL INTO THE ENGINE

using a deft touch, dangle your primer bottle over the engine and allow a drop of fuel to hang out of the tubing. allow the fuel droplet to touch the side of the venturi. Some will go down the side of the engine, some will form a miniscus across the venturi.

Flip the prop once or twice

rotate the prop to close the exhaust port

prime the exhaust port, but blow on it until you can barely see that it wet before opening the port

attach glow plug

use spring starter, wind only one turn.


Engine should fire. It will probably not stay running until it has a little heat in it from 3 or 4 primes being run out. DO NOT PRIME VIA THE VENTURI, USE THE EXHAUST PORT-the venturi prime done earlier is to loosen up the old castor oil and free up a draggy crank in the case. With the stock prop, the needle setting will be about 3-1/2 turns out. The important thing to remember after you get it running is that it will not restart once the needle has been set, you have to open it back up to 4-1/2 to 5 turns because the engine will have cooled off by the time you recover the airplane from where it landed.

Tee Bee

Dave gives some good advice here regarding troubleshooting the .010. My starting regimen is somewhat less disciplined than his, though. I've been known to flood the little engines with too much prime, but not to worry. Just keep the heat on and give her a few extra flips when that occurs. You can hear it run just a little better with each start attempt until she clears out and screams to life. Once a good needle setting has been established, I'm usually able to leave it there for subsequent starts and flights that day with very minor tweaks.

I've run engines that I aquired after long stints in storage. Most of them were a bit problematic getting the venturi passages clear of old castor mung. Once past the fuel draw issue, they usually run like champs. If you run some synthetic/castor blend fuel such as Sig 25 Champion for a while, the engine may clean out a bit and start running better. That's been my experience, anyway.

These little engines are sooo neat and worthy of a little tinker time to experience the thrill of getting some good runs on them. Good luck.

rrragmanliam

My Feedback: (1)

Devious Dave is right on the money. The biggest problem I've noticed with guy's trying to get the .010's running is not opening the needle enough. The engine will burn off the prime but not get enough fuel to run. Open it 5 turns and it will run if all else is well.

rrragman

aspeed

I always put my finger over the venturi while it is running till it almost stops.  I always do it a few times to suck the dried up castor in the passages.  I don't know if the .010 has enough room for fingers.  It works well for planes, weed wackers and old small block Chevies with a towel.

rrengineer

My Feedback: (3)

You have to have the smallest fingers in the world to put one over the venturi with that 3 inch prop spinning a fraction of an inch away. I took the intake body (red plastic intake piece) off as well as the needle body and venturi. I had to replace one of the red plastic intake bodies after finding a crack where it was sucking air. I cleaned out the needle bodies and venturies with a spay of Corrosion-X and ran a fine wire through the three holes in the venturi and through the needle body several times. Of the five engines I am trying to get running, one had a piece of red plastic in the needle body on the fuel line side! It was never going to get fuel that way. It was an engine I bought off Ebay and never got around to running. I didn't think I would have to take so much apart, but I got two of them running now and got a reading on the tach of just under 26 thousand RPM. Not bad considering they only max out at 28,500 or so new. I am using 1/8A fuel I bought several years ago that is 35% nitro and 25% castor oil. Maybe with new fuel and a slightly lower castor content I can get a little more out of these engines. I still have 3 left to clean out and try running, but it just goes to show you should not just leave these little buggers just lying around for extended periods. They are very much like the old British sports cars I restore. They go bad just sitting around. They like to be used regularly and should be. I had not run one of these little ones for quite a while and I just needed a re-introduction in all the quirks to running these little gems again. It's a hoot!

Tee Bee

Glad you're having success!

rrengineer

My Feedback: (3)

Thanks Tee Bee. Now on to the Schoolboy that Rubbernecker cut out for me. I have several Ace pulsers with baby actuators to choose from.
Mike

DeviousDave

I mentioned in an email to RREngineer that CNC'd aluminum carb bodies are available for $13 on Feebay. I picked a red and black one, they are really nice-I haven't mounted one yet, just want to get while the gettin' was good. Someday, Mecoa is going to stop squirting these parts and retire the molds. In fact, I'll bet they have already made a run and that is all that will ever need to be done for the market. Given that they are the same price as the aluminum ones, to me it's a no-brainer to have one around.

rrengineer

My Feedback: (3)

The aluminum intake bodies you are talking about are only made for the .049 and the .010 and the Ebay seller is Riden Fligh. The only ones on Ebay right now are black. Mecoa makes the plastic carb body replacements in red for .010, .020. and up. I agree that you should get a small supply of Mecoa's carb bodies, I have an order in to Mecoa for a few of the carb bodies and a few of the .010 tank back plates. I am always breaking those when tightening the screw that holds it in. Thanks for the heads up on the aluminum bodies. I will order one to check it out. You might also look at a seller on Ebay that goes by the name of engine049. He sells the needle valve bodies with or without a needle valve and spring for .010s in raw aluminum. He claims they are original cox parts.
Mike MacLean

DeviousDave

You can get .020 carb bodies made by the same guy from Bernie on his website.