D.J.

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HiAll

I just bought a COX .020 pee wee for parts for an other enginebut it is such a good looking enginethat Iwant to make itrun again . I have been doing searches and so far the way to goseems to beto soak the engine for 4 days or so in denatured alcohol or WD-40 .
The shaft will move in and out (end play) slowly . it is gummed up . The piston is just about at TDC . The engineis very clean and has no exterior damage or corrosion . The needle is also stuck . Should I try to take the back plate offbefore I soak it or let it soak first?I can fill the fuel tank with whatever I use to soak it in . I still don't have a wrench for the .020 so I have done nothing yet . I see plenty of .049 and .010 wrenches for sale but none for the .020 . I believe that the COX part # is 1030 , Any help in locating one would be appreciated . Any advice and tips for freeing my stuck COXwould be appreciated...... D.J.


PS: I smell like nitro fuel for the first time since the early 70s.

combatpigg

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I wouldn't want to disturb / dismantle the engine until you've given the option of soaking it a week's worth of time.
I'd douse it with Hoppe's gun cleaning solvent.

catracer343

You could also try to warm ti with a heat gun around the cylinder to loosen up the castor...That worked for me a few weeks ago with an old Enya .25. Just use a heavy glove to hold it after heating then GENTLY try to turn it over. Good luck!

earlwb

They use castor oil as the lubricant in the glow fuel. If a engine sits unused for a long time, the castor oil tends to dry out or congeal and get real thick or sticky like sticky fresh varnish on wood that is drying. One method is to soak the engine in some fresh fuel for a few hours, swish it around to try to get the fuel in it real good. Another method is to heat it up with a hair dryer and spray WD-40, Corrosion X or something like that in and on it good. it should free up quite readily. The heat softens the old castor oil and the WD-40 lubes it up and helps to dissolve the gunk in it. it is good to remove the fuel tank so you can get oil and fuel or whatever you are using inside it too. Be gentle with the reed valve, you can clean and reuse it most of the time.

gcb

D.J.,

I would remove the tank and squirt some fuel into the crankcase and the exhaust ports, let it set for a few minutes and gently try to rotate it.

Also squirt some fuel into the reed valve, into the air intake, and on the needle valve to loosen the needle.

If it loosens up, wipe off the fuel and lightly oil the engine. If not, repeat the process. I would not leave the engine in fuel since the nitro can produce rust.

Before putting it away, remove the fuel and oil it.

George

ptulmer

My Feedback: (5)

After reading the title of this thread and seeing CP as the first poster, I was kinda disappointed by a less than whimsical response... It was probably just too obvious for our resident poet.

I've broken loose engines that others gave up on this way: Disassemble as far as you can. Heat gun/ torch the cylinder (not too hot!!!) and turn the crankshaft. If that still doesn't work soak in wd for a bit and repeat step 1.

Yuu

Since you don't have a wrench yet, I suggest to disassemble it as far as possible, and do as Combatpigg suggests; soak it for a week or two in something. I use rubbing alcohol, and put the engine in a small jar on the workbench so I don't forget it. As for the wrench, there was a thread in this forum about the top of the .049 cylinder which did not have the 'flats' in the top fin for the wrench, so the author filed a pair of 'flats' into the top fin on opposite sides, and made it fit a 5/8" open end wrench. Perhaps you can do simular but smaller for the .020 faster than finding a wrench to buy. I imagine the same would work for the glow plug wrench. Good Luck.

BMatthews

Yep, no wrench means leave the cylinder and plug alone for now. But there's no reason at all that you can't take off the 4 backplate screws and carefully twist the tank and backplate free so the soaking in whatever can getin into more spots to work away at the grunge.

D.J.

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Thank you peoplefor all your advice . I have taken step one . I soaked the engine in isopropyl alcohol for 4 hours . I left the jar in the sun and gave it a little shake every 15 minutes or so . I chose isopropyl alcohol because I had some on hand .The needle is now free and it turns out in perfect shape . I filled the tank with alcoholand also squirted it in the air intake as well before I soaked it . I tried to turn the engine over using a wooden bead in the prop location . Nothing yet .I am being gentle at this point . I will soak it one more time before I try and take the tank off . I am still looking for a .020 wrench . I am in no hurry . I have many other projects and I am newly retired . ......... D.J.


Small engines rule . http://motorbicycling.com/

combatpigg

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That's a great looking bike! How well do the chains hold up?

You could expedite the engine lubing process by pulling the head off with pliers. You might see more results by filling a jar with Hoppes, seal the engine in the jar with a tight lid, then duct tape the jar to an orbital sander. Leave that set up running in the hot Sun for awhile.

D.J.

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Thanks combatpigg

I want to be a little more gentle with the process than pliers and an orbital sander . I have time . They have a sonic cleaner at my now old job that I could probably use at lunch time , or borrow over night . I could make a wrench and would ,before I took pliers to this pretty littleengine .

The original chainfor the bike motorwas too heavy . I switched to a normal bike chain and have had no problems since . The bike has over 1600 miles on it now . ...... D.J.

Max_Power

That is a pretty sweet bike!!! If I had less hobbies I would probably be crazy into the motorized bicycle deal...A lot easier to get away with riding on public streets than my 1970 Rupp! If the cylinder is super stuck don't convince yourself a open end wrench (or stamped steel cox wrench)will surely scar parts less than a pair of pliers or vise grips wrapped in a hot pad,etc like CP says...a little heat never hurts either. Its like hard metal lines with flare fittings IE diesel injectors, hydraulic lines etc...Sometimes even a line wrench or box end will round out where strategically positioned vise grips won't. To me a heat gun usually proves a better tool than anything else at freeing up engines that are more than likely just glued together from castor residue. Hope you get her tunning soon! So what kind of bike/engine is that anyway? Todd

66Malibu

DJ,
Just a tip..don't use isopropyl alcohol on any engine that you really like or one with ball bearings due to the water content in the alcohol.The local drug store isopropyl, at least in the US, is either 71% or 90% strength which means it will have from 9% to 29% water in the mixture. Pour some on the driveway or shop floor and the alcohol will flash off in a few seconds and all the moisture you still see is water.
There are as many concoctions to un freeze your Pee Wee as there are modelers. Sometimes I use what an old modeler showed me using straight ammonia but you only submerge it and slosh it around in a jar for about 45 Seconds.....NO MORE or the whole engine will turn dark black. Neutralize with water and WD-40 on afterwards.. The ammonia will dissolve all castor it can get to so disassemble as far as possible.Then a hot hair dryer and a prop to loose everything. You can usually get it really clean from that point on....Good Luck..

fit90

Be careful using anything volatile.  If you do use something volatile like alcohol, MEK or acetone use it in a sealed container to prevent rapid evaporation, condensation then rust.  I prefer Marvel mystery oil on model engines.  It is a mild penetrant.  I have used P B Blaster with a lot of luck on full size mechanical projects; but my experience with it has lead me to believe that it is a for more aggressive penetrant than Marvel Mystery Oil.

What ever you choose I hope it works well for you and that you get a lot of enjoyment from that little engine.

Bob

Tom Nied

Have you tried just some fuel? That always works for me.

LouisB

Agree with Tom here. Had a similar problem with a 049. Just dunk it in a jar with fresh model fuel and put the lid on. No worry about seals, plastics etc etc being dissolved. I left mine for a week and only gave it a gentle shake whenever I managed to pass the jar. It came out perfectly, even the tank's gasket was OK.

If this doen't work, then go to the next phase (heat/ acid/ hammer/ explosive...hehe)

Sport_Pilot

Soak it in fuel overnight.  Denatured alchol will work, but  may have some water and may be corrosive.

combatpigg

My Feedback: (3)

To change out the gun barrels on old battleships, they used straight oil of wintergreen.
You can smell some in MMO.

Larry Driskill

A stuck engine is not a new problem.

Castor is a magic lube and also almost good enough to be used as an adhesive.

A Cox, Fox, McCoy, Norvel, or K&B, left on the shelf long enough will get bored with it all and 'seize'.

I have seen lots of good ideas presented here.

By a fair count I believe we have heard most all of those that we ordinarily and customarily use to try to restore the crippled to action.

What I have not heard is how the hair dryer/heat gun worked.

Is it almost time to put a tad of heat on the case and cylinder?

Doc.316

Wow, a bike motor...I've got one of those (actually two)....nothing runs like a "Fox" when it comes to bike motors!....at least that is what they said in the brochure.

Wow, I think you guys have hit everything that I have ever tried on an engine to free it up...solvents of every sort and heat...seems like that should do it. I did have one that was "rusted" at the ball joint and the crank fell out in my hand.

Steve

flyinrog

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DB cool old Whizzer type replica bike...And like Tom said, I've never run across an engine stuck so bad that some good 1/2a fuel couldnt loosen up within minutes, once it moves a mm either way, keep working it under the fuel should take 5 minutes....Rog

D.J.

My Feedback: (3)

Hi All


The backplate came off easily after the second soaking in ISOPROPONAL (gas line antifreeze) . The piston will still not move so I filled the cylinder with BP BLASTER and will leave it sit some more . Still no luck with the search for the .020 wrench . I ran across a box of 12 for sale and a lot ,with 3 other wrenches on eBay but the sellers would only sell to US buyers . Again I am in no hurry but if I had the glow head off things would be easier so I will wait for the wrench that I need and play with something else in the mean time . I will also tryto soak in fuel after the soak in the BP if that doesn't go well.Heat is also in the future .

I want to thank you all again for your responses and advice . ..... D.J.

Yuu

A soft brass wire brush will clean those threads on the case screws. Might as well clean them up before putting clean fuel in the tank, and getting a piece of swarf under the reed.

Larry Driskill

Swarf ? I had to look that up. Wow, a cool, real word way of saying "junk and trash".


'hope I can remember that.

skaliwag

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Swarf. Perhaps NASSA could use it for an Acronym for some sort of Space Junk. Space ... Waste ... A*****..... R*****.... F****