Golden Bee basic running problem

Without seeing a video or knowing the engine history, I can only guess.

My first tip is engine over compressed and calling for a few more head gaskets. Check engine with stock COX head of normal compression, too.

Second tip is over-propped, but a 2 port cylinder should spin a COX 6*3 faster than the "4 stroking" speed. The 6x3 Master Airscrew prop is heavier than COX, as far as I remember, and it's screw hole larger than the COX prop screw diameter, that, if not bushed by a piece of fuel tube pulled on the screw, may cause prop unbalance...added to a heavy 6x3 prop  may be the compound reason behind 4-stroking.

Check also the radial play of crankshaft, if crankcase is worn too much by prior vibration, the sealing of crankcase is impaired and power is lost.

Check if stock Bee shaft, or aftermarket Killer Bee shaft is in engine? A certain production run of earlier KB aftermarket shafts, easy to identify by a small hole drilled during production  in the middle if the shaft web, had their shaft tip not coaxial with shaft, leading to a wobbling prop..the prior owner of your engine may have fallen victim to a scrap KB aftermarket shaft.

Extended use of high comp head in humid environment may accelerate castor varnish deposition on cylinder internal wall. Check and remove varnish. Instead of devarnisher steel brush I use cold grease remover fluid used to clean household ovens, sprayed on a cotton earbud and swiping cylinder wall. Works efficiently, without scratching cylinder wall, a disadvantage of devarnishing brush.

My other tips would be reed leaking or, missing or flattened O ring on tip of venturi, but you said sealing locations had been found OK.

To me 5 turns on a Bee needle valve seems too much, remove, clean and check NV and carb internal for hardened castor deposits. Manual says 2 1/2 turns should suffice for starting.

You may also want to pull a short silicone fuel tube over the NV and the threaded nipple on backplate to prevent unwanted air ingress into carb  along worn threads of the NV.

Masters 6x3 prop is my standard go-to prop for the Golden Bee. It is optimal for its power curve. If fuel runs fine in another small displacement engine, I suspect something going on with your fuel feed system. Has it been sitting for a while possibly gummed up with dry Castor oil?

I'd check reed area, small thin rubber washer-like gasket sealing the venturi to backplate, etc. Is needle valve end screwing into the tank back sound, tip is good not broken off?

I'm sure it is simple, once you figure it out you'll have it humming in no time,

sounds like your getting plenty of fuel just not regulating it , I would check that reed valve make sure it seals and replace the oring on the Ventura .While the back plate is off remove the needle and check that very small hole at the back plate where the needle comes at end , run a bread tie thats been skint up in it ... 5 turns is to many to start you have a air leak some where . Just have to find it . you can make the oring if you don't have one out of fuel hose .

Disassemble the darned thing, I mean right down to the nitty gritty including..especially including the reed and the pickup tube "spring".  Soak for 20 minutes in Berrymans parts cleaner....don't have Berrymans...soak in 91% alcohol (Walmarts) for three hours then do all the tips mentioned above.  Reassemble, a couple of drops of Marvel Mystery oil in the ports flip over several times, add fresh fuel and power.  3/3 1/2 turns out and WOW another beautifully running Golden Bee.

Whenever I've had a integral tanked Bee that would run but wouldn't peak, I always suspect the reed. Remove the tank assembly, attach a piece of fuel tubing to the venturi and connect to a large syringe, preferably a 5 oz. You shouldn't be able to extract the plunger at all. If it does pull back, it should immediately snap back on release. Push the syringe, and it should allow air to pass. I've found that when the needle valve is in need of opening far beyond the recommended 3-3.5 turns, there's a problem. Once assembled, you should be able to lightly tighten down the needle, pressurize the tank with the syringe. This will immediately yield all air leaks. If air is leaking out of the screen, it's 100% the venturi to tank back o-ring. Air will leak around the tank to crankcase connection and or tank to tank back. In addition, air will also leak from the needle valve and possibly where the spraybar is pressed into the tank back. When you pressurize the fuel tank via the fuel nipples ( capping one off ) air shouldn't leak at all. If it does you may need to also look at the screws. Placing oil on the areas I mentioned will assist in finding them as it will bubble.

Holy smokes, the generosity here is really showing! So many gents taking the time at the keyboard to compose and peck out. Not enough words of gratitude exist!

So..., prior to posting here I actually had it apart twice and installed new gaskets (including the little black donut booger). Very clean inside, and the little donut booger doesn't seem to leak. Needle opens and closes nicely. Pickup tube is open and nicely situated for CL flight. No other leaks. Head gasket situation is a pair of .005s for a total of .01".

The only thing I didn't do was mess with or replace the copper/beryllium reed. It seems to pass the suck / blow test. I avoided replacing it because in the past and on other engines, I found that the mylar or plastic versions wouldn't rotate under the clip as advised.

So that's the latest. I await any further judgements. Thanks!

Dave Mo...

Bench testing, or on a plane? I'm wondering where in the tank the pickup tube is.

Hi Dave, Yea... when someone has an issue with tuning an engine; we all want to give some advice. As a few of the fellas have mentioned; the needle shouldn't need to be opened as much as you've had to.. to get the engine to run. It's worth paying attention to. I also prefer the copper reed to the mylar.. but I'm wondering about your needle and the seat in the back-plate.

Air-leakage around the needle's threads is a common issue.. but i think that there could be an issue with how the needle is seating.

I use these little dental-brushes (flossing type) which will remove "crap" that might not dislodge.. from flushing. You might actually want to flush/brush/flush-again





It was mentioned earlier in the thread.. the benefit of sealing the needle-threads with a short length of silicone glow-fuel tubing. (IE; a sleeve) I forego the "spring" when I apply this to my engines.. but I add a flat-washer above the silicone sleeve, which limits its' travel. From closed; it only needs to open (normally..) 4 revolutions for cold-starting. A proper sleeve of tubing should maintain a seal between fully-closed... and "that-far" open.





Here's some other photos that show the advantages of having the little brushes on hand for general maintenance of our small model engines.













Oh... and filtering your fuel removes a variable from the equation.

Roddie

Great series of photos! My fuel pickup tube and needle valve mod are identical to yours. Insides are clean as a whistle.

My next step: diddle with head gasket thicknesses and give Ken’s reed pressure test a try.

Gracias all!

Dave Mo…

DaveyMo wrote:Roddie

Great series of photos! My fuel pickup tube and needle valve mod are identical to yours. Insides are clean as a whistle.

My next step: diddle with head gasket thicknesses and give Ken’s reed pressure test a try.

Gracias all!

Dave Mo…

I'm sure that you'll get it running like a "top" soon enough!

Well, I just took another hard dive into Ken’s suggestions. Pressurizing the tank showed no leaks. But I did spy a small, semi-circular break in the otherwise beautiful copper reed. Perhaps this is the Eurika moment!

No floppy discs around this house anymore. So it appears a reed order is in order. Who supplies the best replacement reeds (the ones that rotate under the e-clip)?

Thanks to all for your great help. And a bit of hat tip to Ken as well.

Dave Mo…

Make you own Dave >> https://www.coxengineforum.com/t9647-cut-your-own-reeds?highlight=cut+you+own+reeds

Burnie of Cox International has good reeds along with Matt of EX Model Engines.

But, If you are overhauling the engine, why not purchase an overhaul kit that has everything you'll need to rejuvenate your engine to where it is like new?

Below are the websites for the overhaul kit that you'll need.

Cox International website -- Overhaul kit:
Golden Bee Overhaul kit

Cox International has more for a rebuild kit. I like it because it has a new fuel line pickup and spring.
Where the old fuel pickup is probably hard and brittle, and the new spring is not corroded, and the screws might be corroded as well?
(Reed, Pick-up line, Venturi gasket, Fuel tank screws, Crankcase gasket, Pick-up line spring)


EX Model Engines website --- Overhaul kit:
Golden Bee overhaul kit

Ex Model Engine's has what you really need to a basic rebuild --- the gaskets and a new reed.
(Crankcase Gasket, Venturi Gasket, Glow Head Gasket, Mylar Reed)

It is up to you to pick the one you want?

Much obliged, getback and sosam. EXmodel has my order.

Dave Mo…

roddie wrote:Hi Dave, Yea... when someone has an issue with tuning an engine; we all want to give some advice.

This turned out to be an interesting thread and finally nailed down to a cracked reed I gather.

Roddie provided a good detailed methodology step by step on engine cleaning.

Regarding the comment on advice, everyone here who posted has restored basket case engines. Some are better at explaining than others. Good examples abound, captured in past threads in this forum.

Also, it goes to show that without being there in person to fully examine the engine, forum troubleshooting is indeed a difficult way because we were basically clueless, attempting to "read through the lines".

So, what does one say, exactly?

Example, I've used wired felt pipe cleaners (of the tobacco smoking variety) to clean fuel passages. And, dare I say, poking a small diameter salvaged copper wire to clear holes. Sometimes boiling in antifreeze clears them.

Bottom line, we just "git 'er done". The 'splaining comes later. I'm glad to hear that the engine is on its way to being restored in running condition.

Hi Dave, If you happen to come across Cox spare-parts/Cox parts-engines etc. Be sure to salvage any copper reeds and circlips from backplates/carbs. The early Cox .049 product engines had what's referred to as the "Postage Stamp" backplate. Those all had copper/star-shaped reeds with circlip type retainers and superior fine-toothed (128 tpi) needle-valve assemblies.





There were differences in the wire size used on the circlips. It can vary as much as .005" in my experience.







The Mylar (oblong shape) reeds are almost always .005" thickness.. and the copper (star-shape) reeds are thinner.. at .001" to .002" average. It's important therefor; to be sure that the circlip you're using is NOT pinching the reed.. preventing it from functioning properly.

I've made my own reeds.. just to see if they'd work.. and they did. Having a quality vernier/caliper for measuring thickness is essential.. unless the stock's thickness is known.

thread-link covering that

Love the photos, Roddie on the venerable trustworthy red Delrin postage stamp back (as an example) and important "must heed info" on retainer wire diameters, for successful reed operation, given type of back and reed used. And, reed making.  


Love these old type backs because they were bulletproof. Still have my donor engines from my Cox P-51B and L-4 Piper Grasshopper 55 years ago. (It's been that long. A bit of trivia, but the P-51B was slightly faster being more streamlined than the P-51D with bubble canopy favored by pilots for increased rearward visibility. I love it because it is different. )

Wished I left the one in my Goldberg Little Toot bipe with Perfect 1/4 oz. (I believe a touch less than 8 cc) wedge tank and GB EB-1 engine mount instead of changing out with Testor's Red Head .049 with tank.

It balanced better.

And that Brown and Sharpe dial caliper is a classic old school quality instrument. Haven't seen one of those since the 1970's, when as college student help, worked in a machine shop with Bert, a German watch maker by training. I learned German attitude toward perfection, which Bernie @Cox International fully understands.

(I saw that meticulous attention to detail in my new Tee Dee .049 I bought from him recently.)


I return control of this thread after a visit from The Outer Limits.

The saga continues (sort of). Replacement copper reed didn’t do anything. But…, swapping out the Number 5 P-C combo for a Number 1 version finally got things going! Holy moly what a trial, but she runs.

Well, a good, strong unsteady run at 4 turns open on the needle. Had to diddle the needle in and out a bit to keep ‘er at top speed. But what a beautiful sound.

By the way, this Golden Bee is like new old stock. However I wonder about the #5 P-C. Might be a Frankenstein engine (got it as a gift).

To steady out the run:
1) Play around with different head gasket thicknesses, or
2) Re- replace the little black booger gasket with yet another one. I’ve got some on order.
3) Anything else?

Dave Mo…

Dave, I think the stock GB had No2 cylinder, so with a No1 it is already a Frankenstein?

Did you check the varnish in the cylinder that may brake the piston movement? This was one of my tips..

One thing that no one seems to have commented on-and it does potentially impact on the problem-the classic Babe Bee/Golden Bee/QZ/Black widow needle is steel-some are quite hard....and BRITTLE-that means-fairly obviously-they can snap. Invariably-that means the extreme tip-possibly only as little as 0.5 to 1mm.

The immediate consequence of this-especially in an engine where the damage hasn't been noticed-or parts have been exchanged-is the needle is now fractionally shorter-but now wider-in the tapered portion. Equally obvious is that it will now screw in further down the threaded insert-even if the owner hasn't realised.

When unscrewed--however many turns-the metering effect on fuel-will be different when compared to the original-because you now have effectiely a bigger blunter needle now blocking the fuel metering jet-so it might well require more turns open to get the engine to run. If the broken end is both 'blunt' and not at 90 degrees-this could well affect the setting when trying to peak the motor

I have had over the years a number of engines pass through my hands with such damaged needles-the only way you tend to notice is if you do a side by side comparison with a NIP original spare needle.

I note that the later Cox designs -Space Hopper TD, Medallion, KB, Queen Bee etc all use needles where the tapered section is thicker than the Babe Bee type-which of course goes back to the very first Cox made engines-the Space Bug and Thermal Hopper-and none seem to suffer any problems in setting...

ChrisM
'ffkiwi'

Ah, now we’re talking! I swapped out the needle to an older version and she runs just fine. Sweet motor it is. Thanks, Chris.

Balogh: The P-C are very clean. Like so many of the Cox 049s here stateside, the parts I have come from motors run only once or twice. I have a source for an original Number 2 cylinder and I might go with that for longer flights.

Dave Mo…