starting a sure start

Another way:

Close the needle valve and learn to burn off primes first. I am guessing you have the engine mounted on some kind of test stand (board?).

Use your self-engaging spring starter by turning the prop one turn clockwise. Connect the glow plug power (alligator clips) and prime the cylinder with one drop of fuel in the exhaust port. Now release the prop by removing your hand quickly. The starter spring should cause the engine to start and burn off the fuel in the cylinder.

When you can do that successfully, move on to running from a tank.

Making sure the top of the tank is below the needle valve so it won't gravity feed into the crankcase, open the needle three turns. Start as before.

As far as nitro, I have used as low as 5% and as high as 35%. Standard Cox fuel was 15% and their racing was 25%. Oil should be in the 20% range with at least half of it castor. Be careful of car fuel because some of it does not have enough lube for airplane use. You should be able to find lube contents online.

Good luck with it.
George

thats right. try to find the right starting mixture first.
if it sort of bubbles and doesn't get to any rpms, it was too much fuel.
you know its the correct amount when the engine (without the tank) turns up almost to its max rpm, and then stops.
usually, its enough to drip some in there so it forms a bulge on top of the piston. that should be perfect. otherwise,
get the fuel out of the engine first, like gcb just said.

Hello, G-Money. The above posts cover just about everything that is needed but if you want, I have a Sure Start manual that you can download.

Check to make sure fuel is flowing from the tank to the engine, and tank is set high enough behind the engine. On a sure start you can put your finger over the air intake vent and with the needle valve open give it a few flips before you connect the battery and that will pull the fuel through the line. Or if you have a long run. you may have to block a tank bent and force it to flow to the engine with the filler. Don't do it if you know the cylinder is already wet. Then do what everyone else said and it should start if. If not, check that the glowplug works, and there are no leaks between the crankcase and the backplate. If you have to take it apart, do a suck/blow test to make sure the reed is opening and closing. And then wipe your mouth off.

No need for removing the glow plug during routine starting. The perfect mixture for the Coxes is about 25% nitro, 20% castor oil, not synthetic(though some people mix in some synth), and the balance is methanol. Lack of castor will ruin the piston rod at the ball socket. Glowplugboy is a popular brand that my engines love. I'm too new to post a link, but look up Glowplugboy 1/2A fuel on eBay. He has his own site too.
It has 17% castor and 24% nitromethane.
And please try to avoid using the word "carburetor" on a reed valve engine. No offense to those that do. The Cox Tee Dee and Medallion are two that actually do have a carb.

The cox tee dee doesn't Evan have a carb it uses a venture unless someone adds a carb.

Thank you all, I'm going to go try some of these things and then get back to tell if it worked or not. Thanks, Phil (the kids call me G-Money)

RknRusty wrote:Check to make sure fuel is flowing from the tank to the engine, and tank is set high enough behind the engine. On a sure start you can put your finger over the air intake vent and with the needle valve open give it a few flips before you connect the battery and that will pull the fuel through the line. Or if you have a long run. you may have to block a tank bent and force it to flow to the engine with the filler. Don't do it if you know the cylinder is already wet. Then do what everyone else said and it should start if. If not, check that the glowplug works, and there are no leaks between the crankcase and the backplate. If you have to take it apart, do a suck/blow test to make sure the reed is opening and closing. And then wipe your mouth off.

No need for removing the glow plug during routine starting. The perfect mixture for the Coxes is about 25% nitro, 20% castor oil, not synthetic(though some people mix in some synth), and the balance is methanol. Lack of castor will ruin the piston rod at the ball socket. Glowplugboy is a popular brand that my engines love. I'm too new to post a link, but look up Glowplugboy 1/2A fuel on eBay. He has his own site too.
It has 17% castor and 24% nitromethane.
And please try to avoid using the word "carburetor" on a reed valve engine. No offense to those that do. The Cox Tee Dee and Medallion are two that actually do have a carb.

hm, i'd be a little careful with 25%. the more nitro the more heat, and that might make your glow plug brake faster.

I run all my cox engines on 25% now and I have never burned out a glow plug prematurely.

GermanBeez wrote:

RknRusty wrote:Check to make sure fuel is flowing from the tank to the engine, and tank is set high enough behind the engine. On a sure start you can put your finger over the air intake vent and with the needle valve open give it a few flips before you connect the battery and that will pull the fuel through the line. Or if you have a long run. you may have to block a tank bent and force it to flow to the engine with the filler. Don't do it if you know the cylinder is already wet. Then do what everyone else said and it should start if. If not, check that the glowplug works, and there are no leaks between the crankcase and the backplate. If you have to take it apart, do a suck/blow test to make sure the reed is opening and closing. And then wipe your mouth off.

No need for removing the glow plug during routine starting. The perfect mixture for the Coxes is about 25% nitro, 20% castor oil, not synthetic(though some people mix in some synth), and the balance is methanol. Lack of castor will ruin the piston rod at the ball socket. Glowplugboy is a popular brand that my engines love. I'm too new to post a link, but look up Glowplugboy 1/2A fuel on eBay. He has his own site too.
It has 17% castor and 24% nitromethane.
And please try to avoid using the word "carburetor" on a reed valve engine. No offense to those that do. The Cox Tee Dee and Medallion are two that actually do have a carb.

hm, i'd be a little careful with 25%. the more nitro the more heat, and that might make your glow plug brake faster.

I know that the original cox super power fuel was 25% or very close to 25%. I don't recall any of my heads burning out quicker.

Were there not 3 cox fuel: glow power,flying power and racing power which was 35% nitro or am I wrong some one was selling cox fuel formulations and original documents and the were 3 formulations.

nitroairplane wrote:Were there not 3 cox fuel: glow power,flying power and racing power which was 35% nitro or am I wrong some one was selling cox fuel formulations and original documents and the were 3 formulations.

There was different cox fuels. I don't remember the exact names for them right now. I know the cox racing fuel was 35% nitro I remember that.

I knew that was it ibwas goin to buy the formulae and documents but I was a US auction and I was asleep when the ewing soon notice came theough.

there was several different cox fuels. i have the cans around here somewhere. i have my super power fuel, flight power fuel, glow power fuel, special blend fuel, racing fuel and a old thimble drome glow fuel can. Thats what I have. I couldnt tell you all of what the %s were but that is what I have

Back to the original question.

How sure are you that the copper gasket is in place between the cylinder and the head? If it is missing the problem described will occur as the compression ratio will be increased considerably.

My Sure-Start starts surely.

As a kid I used the blue can of Cox fuel and the red can called racing fuel. On RCG most members agree the blue can is 20 something and the red can is 30 something percent. I've never used less than the 20 something blue can. The 30-35% will give it more RPM but it likely wears out the soft cylinder wall and the con rod ball socket faster. Not worth it unless you race. I really like the 24% Glowplugboy fuel.

nitroairplane wrote:The cox tee dee doesn't Even have a carb it uses a venturi unless someone adds a carb.

Oh, I guess I'm mistaken. Lots of people refer to it as a carb, so I've been influenced badly after all.

RknRusty wrote:

nitroairplane wrote:The cox tee dee doesn't Even have a carb it uses a venturi unless someone adds a carb.

Oh, I guess I'm mistaken. Lots of people refer to it as a carb, so I've been influenced badly after all.

I always refer to it as a carb, so does cox. All their manuals and parts lists describe it as one. "Carburetor Body", "Carburetor Assembly" Many people call it an intake as well.

it is the part of a 2 stroke engine that mixes fuel and air, and is connected to the crank case. its a carburator. its shaped like one, it works like one. period. and so does the reed valve carb. it has injector nozzles, it mixes fuel and air through the venturi effect. it' just more compact
so it doesn't take that much room in the tank. THEY ARE ALL CARBS.

I mostly rub 010 and 020 engines and I dont ever mess with anything lower than 20%

Often what passes for a "carburetor" is actually and air intake restrictor. A true carburetor would meter fuel as well as air.

Initially early Cox "throttles" were exhaust restrictors fixed to the cylinder exhaust ports. Over time Coxes where more effectively throttled by air intake restrictors which are currently available from vendors such as www.coxinternational.com (Bernie and Nicole are GREAT!)

I'm running a Dumas "Lil' Swamp Buggy" with a Sure-Start .049 and equipped with an air restrictor throttle and "Type B" head coversion for lower RPM. With that arrangement I have a good range of operational RPM (6K-16K). It's great for repectfully"patrolling" the Canada geese at my son's lake place. :lol!

SuperDave

A carburetor is a device that delivers a fuel and air mixture to an internal combustion engine. It does not need to be variable. Don't confuse that with throttle.

We sometimes create our own definitions and for CL, the generally accepted treminology is venturi, and for RC, the generally accepted term is carburetor. I'll bet when someone uses the wrong term you still form the correct image in your mind. Potayto, potahto.

Remember also that the Medallion uses a spraybar in the venturi, and the TD uses a three hole sprinkler system. Both are still considered venturies.

At least that's the way I understand it.

George