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Engine basics => Engine set up tips => Topic started by: YakNine on March 25, 2016, 06:55:36 PM

Title: OK Cub .049 B
Post by: YakNine on March 25, 2016, 06:55:36 PM
I bought a box of model stuff last year at a flea market. One of the engines was an OK cub .049B . I loosened it up with a heat gun and some liquid wrench cleaned out the NV and it started right up. I have run 2 tanks through it and it's a neat little engine, it starts right up and I think it's pretty darn cute to boot. On the right side the casting must be a little thin because I think one of the threads cut through the case and it has a little leak there I found it when priming the engine when you prop it a little bit of fuel squirts out. You can hear it hiss a little bit when flipping the prop. I guess it has been like this for a long time as the castor goo was pretty thick in this area. It is wet there when it runs but it doesnt shoot out fuel. I don't know if I should live with it , try and seal it , or get another crankcase, I imagine I could put a little dab of JB there to seal it. I am going to put this engine on a Pee Wee Pup just for fun flying. T.J.
Title: Re: OK Cub .049 B
Post by: Dane Martin on March 25, 2016, 07:24:11 PM
I personally would fix it. Just cuz it's fun to work on them. I would disassemble it and soak the case in your favorite degreasing solvent. Then inject the JB inside the hole with a syringe at the very bottom. Then install the screw to where it pushes the excess out off the hole. Then take the screw out and let it cure. Then run a tap through it and bada boom!

I don't like putting it just on the outside just cuz I'm afraid of fuel soak killing the bond after time. But, you could probably find a case for a couple bucks also... Lol
Title: Re: OK Cub .049 B
Post by: YakNine on March 26, 2016, 03:32:53 PM
Wondering if the wrist pin floats free in the rod on this engine or if mine is castored tight, before I run it any more. T.J.
Title: Re: OK Cub .049 B
Post by: BillP on March 28, 2016, 03:02:54 PM
I'm not a big fan of JB Weld for structural repair on metal but it will probably work on this application. It will also creep (before kicking off) on its own or can be pressed through the hole when at ambient temp or with heat if the hole is pin head size. I would take it apart, clean and dab/press JB Weld from the inside and let it sit a couple days at room temp before use. Whatever undesirable "flash" is left over can be sanded or filed off without much hassle.



Title: Re: OK Cub .049 B
Post by: rustler on March 29, 2016, 02:57:56 PM
You may still be able to get spares from the maker. They were up and running at least until quite recently.
Title: Re: OK Cub .049 B
Post by: YakNine on April 02, 2016, 07:51:53 PM
Well I just got a parts engine off EBay, hopefully it's better than the one I have. T.J.
Title: Re: OK Cub .049 B
Post by: YakNine on April 07, 2016, 07:11:07 PM
Got the engine from eBay the casting was much thicker than the original. Put it together and it runs fine. T.J. I
 
Title: Re: OK Cub .049 B
Post by: Dane Martin on April 07, 2016, 07:12:05 PM
Awesome to hear! Power for a baby ringmaster?