Need info about Cox Sure Start .049 engine please - RC Groups
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Apr 07, 2008, 01:08 AM

Need info about Cox Sure Start .049 engine please

Hi, I am new and have been messing around with electric parkflyers for about a month, but i don't like having to mess with batteries not lasting long enough and having to wait for them to recharge and all.

But anyway I found on the cox website that you can buy one of these little .049 engines for about 8 bucks! I want to get into glow engines without having to pay a whole lot of money, at least not to start out with.

What I need to know is if this includes everything you need to make the engine work, or do you still need a fuel tank or anything else. Obviously you have to buy fuel, but is there anything besides that? Also is the fuel gravity fed or will it draw in the fuel from a tank on its own?

Any advice would be greatly appreciated, Here is a link to cox's website in case anyone needs to see it for reference.
just search for item # Cox 8901 .049 Sure Start Engine
Again any help is appreciated, thanks- Jody
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Apr 07, 2008, 01:16 AM
Registered User
You will need a fuel tank and a glow igniter and something to get the fuel from the bottle to the tank. Either a pump or a fueling bottle. Also, as the glow heads tend to be expensive, you might want to buy a glow plug adapter for it so that you can use a regular plug.
Apr 07, 2008, 01:55 AM
Thank you Jupeli for your reply, Do you happen to know how far away the tank can be mounted from the engine, will the fuel be sucked into the engine?
Apr 07, 2008, 04:51 AM
Registered User
I don't know how far it can be mounted but in general, it is better to be mounted as close as possible. In most planes there is a plenty of room for a tank just behind the firewall.

By the way, don't forget to buy some fuel tube also.
Apr 07, 2008, 12:04 PM
Deletedfor proving Nauga wrong
they should be named "might start" instead of "Sure Start"

The $8 deal won't have a fuel tank or "starting equipment"

You need a special adapter for the Cox glow head... or you can use a couple of aligator clips and "creative connection"

Cox engines LOVE NITRO... use 30% heli fuel.
Apr 07, 2008, 02:29 PM
Registered User
I have actually managed to run a Sure Start on 5% Cool Power but I am going to get some 20% nitro 20% castor fuel for my Cox engines. No starting issues though but maybe still not the best engine for someone new to glow. You'll save a lot of swearwords by asking someone more experienced to show you how it works.

If one buys a glow plug adapter head so he can use a regular glow plug, couldn't he just use a regular glow igniter? (I use Cox glow heads so I have got no real experience on those adapters.)
Apr 07, 2008, 03:28 PM
Registered User

I just mounted a new SureStart to a board clamped in a vise and fired one up yesterday. Took the tube off the back so I could flush mount it and hooked on the tank. Used 30% helimix with enough castor to top off the new gallon bottle.

Since I still have a 30yr old Cox glowplug clip hooked to a new 1 1/2v hobby battery it was a simple setup. Used a baster type fuel bulb to fill/drain a 1oz tank.

Set needlevalve 2 1/2 turns out and it fired on the first flip (after prime). Started and ran on the 3rd and seemed to go on forever! Was growing stronger and stronger and I finally leaned it out to kill it after a half tank.

Its been many years since I ran one and I forgot just how neat they were,

Apr 07, 2008, 04:05 PM
Deletedfor proving Nauga wrong
Yes, you cna use a regular ignitor with the adapter head.

You can make an adapter head from a bad stock Cox "plug/head"... you just need the correct tap for the plug. (10-24?... been a while since I did that) Drill out the center, tap it and then it works.

I use a "flavor injector" syringe from the grocery store to fill the 1/2 A and smaller engines that I still have.
Apr 09, 2008, 08:53 AM
Registered User
Well, I may have replied too soon as last night I reinstalled the engine on a solid test mount with one of those quickmount doodads with the snap on film canister tank. (Its really clever)

Anyway, the engine fired right up but leaned out and died at less than a quarter tank. (Approx 2 min. run time). I restarted and richened the mixture about a quarter turn and it ran out the tank...approximately another 6 minutes. During the run the rpm noticably fluctuated ending with the typical ending smooth higher rpm as the fuel ran out.

Refilled the tank and after a couple of minutes restarted. The engine ran approximately 1 minute then died. Couldn't restart and I felt it may have flooded due to the excess fuel around the ports.

Anyway, I turned the prop until I could hear it cooking and disconnected the battery clip and drained the fuel tank.

Will try again tonight. Hopefully its just a break-in process.

All those years as a kid running the tar out of these things I never had a problem with one once it ran out a tank. Sure hope this one wakes up.


Apr 09, 2008, 10:46 PM
Registered User
It may have been flooded but right now I can't tell. Initially I closed the needle valve and fliped on just prime till it fired. Then opened 2 turns and it fired and ran for about a minute then died. Wouldn't start until I opened it another quarter turn and then ran the tank out. 12 minute run!

Had dinner and came back out and it wouldn't do any more than a burst and die for a good bit. Then it ran but wouldn't build any power so I gently opened up another half turn on the needle valve and it ran like a top. But halfway thru the tank it dropped rpm and I noticed fuel bubbleing around the cylinder and it soon died. Let her cool a minute, topped off the tank and it didn't want to run. Leaned back to 2 1/2 turns open on the needle valve and she fired right up. Ran very stable for 1/2 tank, then erratically for a couple of minutes. RPM's were down to around 8600 and then it would run up to near 10000 and flutter all in between. Then for the last quarter of the tank it sped back up to over 12000 and ran well until the tank ran dry. 15 minute run!

When turning between 12000 and 12800 the engine sounds downright strong. Seems stable when turning 11500-11900. Below that you don't know if it will recover or die.

It now has around 4 oz. of fuel thru it. (45 minutes +/-) Any idea how much it takes before one is broken in really well?


Apr 10, 2008, 07:16 PM
Master of the Figure "9"
hogflyer's Avatar
Clay -

Here's how I break-in a Sure Start:

Pull it apart and clean everything well.

Check the ball/socket for play and reset the socket.

Reassemble using after run oil or castor oil. Don't forget the copper gasket under the glow head.

Make sure the fuel tank is as close as possible and centered on the center of the crank case.

Open the needle valve 2-1/2 turns and start the engine.

Once the engine has started I'll run 1/2 - 1 oz through sloppy rich. Usually about 3 to 3-1/4 turns open on the needle valve.

Reset the needle valve to 2-1/2 turns open and fire it back up. Then set for peak and back off 1/4 turn.

This seems to work good for me, and I haven't had any problems with them using this procedure.

Your engine is broken in by now. Start it a 2-1/2 turns, peak it and back it off 1/4 turn and you should be ready to fly. Also check to make sure the glow head, back plate and cylinder are all tight. For a prop, the Master Air Screw 6 X 3 seems to be a good choice since the Cox props are getting hard and expensive when you find one. Next time you order a Sure Start, order 10 - complete engines with the glow head are a buck cheaper than just the glow head alone, and the shipping is the same regardless if you buy one or 10 engines.

The pictures show a SS installation with a 1oz fuel tank.

Apr 10, 2008, 10:37 PM
Registered User
Gotta be honest and say that in all the years I ran the fool out of .049's as a kid, I never heard of resetting a ball socket on one until reading about the SureStart woes. Don't have those tools and hope I won't need them. But you can bet I'll pick one up if I come across it now.

Thanks for sharing the pics Hogflyer. I did get a separate tank but once I saw the Slickmount I ordered a couple. Sure is nice and the tank draws down to virtually dry.

On this engine I would flood out if I tried to richen it to that many turns. Its just finicky I suppose. I've a couple more and it will be interesting to see if they are better or worse behaved.

I solo'd myself on my Hobbistar today and need to start on the Indicator build soon. Space in my car is at a premium and I'm hoping the .049 stuff will scratch my itch just as good!


Apr 11, 2008, 04:12 PM
Master of the Figure "9"
hogflyer's Avatar
Clay -

Congratulations on the solo - the grin will slowly go away in a week or so.

If you go to or Dave Fritzke's site ( and you'll find a number of good 1/2A plans to download for free.

The plane in the picture is a traveling plane that I had for a while and it's now in Canada - next stop after that will be Japan. The plans for the can be found at, and lots of information in RCU 1/2A forum under the Postal Plane thread.

Apr 16, 2008, 05:00 PM

what is this?

My surefire finally arrived, but it did not come with any paperwork, just the engine and spring inside some bubblewrap. what i need to know is what is the tube on the top behind the glow plug and needle. does it just suppory the needle itself or does have purpose? also can I remove this in order to flush mount the engine?
This is my first glow so forgive my ignorance. -Jody
Apr 16, 2008, 06:16 PM
Master of the Figure "9"
hogflyer's Avatar

That tube behind the needle valve is the "Choke Tube". You can remove it if you want since it's not needed for the engine to run, but I've found it does make priming easier. Since you have a remove fuel tank, cover the tube with your finger like you do a standard carb and turn the prop through until you see fuel moving through the fuel line. The weight savings will be negligible if you remove it, and I personally don't feel its worth the time or effort to remove it.


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