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Author Topic: OK Cub strter removal?  (Read 1378 times)

Offline Andrew Tinsley

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OK Cub strter removal?
« on: January 07, 2014, 08:06:51 AM »
 Things are getting sad around here! I am trying to take a spring starter unit off an ok Cub 0.049 (Quite why I don't know). Oh yes the starter spring has broken (surprise surprise!). Well it seems as if it may be a good runner, decent compression and the like (Oh it has the famous Cub blunt NVA, yet another job, why do I bother?).
  Anyone know how to get this starter off before I take a vice grip to it?

Andrew.
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Offline GGeezer

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Re: OK Cub strter removal?
« Reply #1 on: January 08, 2014, 06:13:33 PM »
I suspect it is a press fit. What I would do is heat the starter unit with a propane torch or a hot air gun. Cool the crankcase with a cold wet rag and see if it will fall off.

Orv.
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Offline Andrew Tinsley

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Re: OK Cub strter removal?
« Reply #2 on: January 09, 2014, 01:56:48 AM »
Hello Orv,
The prop drive plate is plastic and the front of the starter unit is an extension of said plastic drive plate. So a torch is out . There is a very small hole through the periphery of the plastic drive plate and this lines up with a small hole in the plastic forming the front of the starter unit. Maybe some sort of pin? Anyway, maybe a freezing of the engine will help? The plastic may have a lower coeff of expansion than the crank, so perhaps easier to pull off. I shall give it a try as I am sure the drive plate is just forced onto the shaft. looks like brute force and ignorance will win the day!

Thanks,

Andrew.
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Online john vlna

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Re: OK Cub strter removal?
« Reply #3 on: January 09, 2014, 06:31:21 PM »
Andrew
Drop OK Cub an emil, they will probably tell you how  to do it. OKENGINES@AOL.COM
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Offline Andrew Tinsley

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Re: OK Cub strter removal?
« Reply #4 on: January 10, 2014, 09:55:07 AM »
Hi John,
Thanks for the OK contact address, I could do with some glow heads and the web site is not good! Regarding the removal of the starter mechanism, I will have to be desperate to call OK. The real fun in messing with engines is learning the hard way!!!!!!! But if I don't get it figured, then I will do as you suggest. Right now the engine is in the freezer (my wife is away!). I have a small puller standing by. Will let you know if it works.
As an aside, the one reason I would never go electric is because I love working with and on these cantankerous IC engines! If you just want to fly, then electric is easy, no challenge in the motive power dept. Someone said I had only 10 years left, before electric took over all C/L. That is just rubbish, I make my own fuel and I have enough engines to last me several lifetimes. Mental note ......... don't buy anymore engines!

Andrew.
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Offline GGeezer

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Re: OK Cub strter removal?
« Reply #5 on: January 10, 2014, 07:26:47 PM »
Hi Andrew,
I wasn't aware that the starter was plastic. Plastics in general have a greater coef. of expansion than aluminum so heat is still the answer. If the starter unit isn't important to keep intact, Heat the unit with a hot air gun or hair dryer and see if it will move or rotate. If not, keep heating it until the plastic gets very hot (close to the melting point) and it is sure to come off. If the plastic is nylon, the same as the tanks on the .049A, then the material should get rubber-like at below the boiling point of water (100 C) and melt at around 220 C.

Orv.
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Offline Andrew Tinsley

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Re: OK Cub strter removal?
« Reply #6 on: January 11, 2014, 10:59:15 AM »
Hello Orv,
Thanks for that advice. I have been busy on domestic duties, so I have not had the puller on the chilled engine yet. I didn't realise the coeff of expansion was higher for plastics.I will do as you suggest.

Thanks again,

Andrew.
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Offline Tim Wescott

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Re: OK Cub strter removal?
« Reply #7 on: January 11, 2014, 11:08:07 AM »
Chilling the plastic will also tend to make it more brittle and hence prone to breaking when you try to remove it.  If I were at all concerned about keeping the starter I wouldn't mess with it when it's below room temperature.  Since it's cold anyway the best thing to do may be to boil a cup of water in the microwave and dip just the nose of the engine into the water.  That'll warm up the plastic faster than it warms up the aluminum of the case.  At that point the plastic should be as loose and un-breakable as it'll get, and the metal will be small (small-ish, at least). 

Then see if you can pull the starter.
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

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