Need help with Cox .049 engine

DeHavilland Thu Mar 01, 2012 12:39 pm

Hello everyone, a friend of mine gave me some old control line models that came with a cox .049 engine but it is seized, any way I can fix this? I have taken it apart and oiled it but it still won't work.

Cox International Thu Mar 01, 2012 12:42 pm

Here is a link to some engine guides, incl. a troubleshooting chart:

http://coxengines.ca/pages.php?pageid=19

**Cribbs74** Thu Mar 01, 2012 12:49 pm

DeHavilland wrote:Hello everyone, a friend of mine gave me some old control line models that came with a cox .049 engine but it is seized, any way I can fix this? I have taken it apart and oiled it but it still won't work.

Apart from the troubleshooting guide from CI you may want to familiarize yourself with the engine type as to the specific starting method, most Cox engines start the same though. Engine manuals also found at the aformentioned link.

SuperDave Thu Mar 01, 2012 12:51 pm

Suggest going to the Trouble Shooting Guide provided by Cox International. The topic has been covered many times in our "search" file.

The engine is likely seized by castor oil residue which is not at all uncommon in engines that haven't been run in some time. Hoppe's #9 gun cleaning solvent works very well to loosen "frozen" Cox engines. Let it soak in then turn the crankshaft back and forth in small increments.

Would need to know the type and displacement of the Cox engine to give further details.

DeHavilland Thu Mar 01, 2012 1:00 pm

Ok thanks for the help, The troubleshooting guide said to soak it in fresh fuel overnight so I think I will try that. Airplane

**Cribbs74** Thu Mar 01, 2012 1:06 pm

Is the engine still seized? You said you took it apart.

SuperDave Thu Mar 01, 2012 1:18 pm

DeHav:

The key is to let the solvent SOAK in and that takes time possibly days. Be patient.

The good news is that, depending on the type of Cox engine you have, there are an abundance of parts available from our several vendors.

DeHavilland Thu Mar 01, 2012 2:24 pm

I did take apart mostly, the only problem is I can't get the piston out of the cylinder.

SuperDave Thu Mar 01, 2012 2:45 pm

DeHavilland wrote:I did take apart mostly, the only problem is I can't get the piston out of the cylinder.

Don't use force to get it out. Put solvent in the cylinder an let it soak. The crankshaft may be frozen too, same problem same solution. Do you have Cox wrench to remove the cylinder head? Don't try it without or you'll likely damage a cooling fin. Do NOT use pliers!

(We can get you through this if you follow our suggestions)

**RknRusty** Thu Mar 01, 2012 6:22 pm

The piston might loosen up with a heat gun or a hair dryer. Soaking is probably best. Hopefully the piston hasn't shared any oxidation with the steel cylinder. If it has rust, it'll be best to get a new piston/cylinder set.

Scroll down this page for choices:
http://coxengines.ca/home.php?cat=27

SuperDave Thu Mar 01, 2012 6:58 pm

This is a Cox .049 wrench need to disassemble them properly:

Need help with Cox .049 engine XctF2B.tmp

See details

Cox .049 Wrench
SKU: 490WREN

Our price: $ 3.95

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