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Author Topic: OS Max LA -15 back plate.  (Read 2002 times)

Offline John Rist

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OS Max LA -15 back plate.
« on: September 15, 2016, 02:55:08 PM »
I scored OS Max LA 15 (Blue) on Ebay.  It looks like it will be a good runner but the back plate leaks.  When running I see bubbles coming out.  Does the plastic back plate of a 15 use a gasket? Is their a metal back plate that fits? Does anyone make an after market back plate? What is the best way to stop the leak?  I have cut off the remote needle.
John Rist
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Offline Robert Zambelli

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Re: OS Max LA -15 back plate.
« Reply #1 on: September 15, 2016, 03:03:09 PM »
John: I have been running an LA 15 for about ten years.

I removed the backplate gasket when I bought it, sealed it with a bead of silicone sealant and it has never leaked.
It has around 300 flights.

Bob Z.

Offline John Rist

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Re: OS Max LA -15 back plate.
« Reply #2 on: September 15, 2016, 03:28:39 PM »
John: I have been running an LA 15 for about ten years.

I removed the backplate gasket when I bought it, sealed it with a bead of silicone sealant and it has never leaked.
It has around 300 flights.

Bob Z.

That was the direction I was headed.  I removed the back plate and their was no gasket.  I have a tube of pure GE silicon sealant that should work.

Thanks Robert for the quick reply.
John Rist
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Offline John Rist

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Re: OS Max LA -15 back plate.
« Reply #3 on: September 15, 2016, 04:19:34 PM »
I cleaned it up, applied a little silicone sealant, and reinstalled the back plate.  The motor was now binding and would barley turn over.  An inspection determined that the crank pin was hitting the back plate.  It appears the reason the back plate was leaking is that that it was loose to prevent it from binding.  Another funny thing when I started to clean the engine with alcohol the blue color started to come off.   Some one has sprayed painted this bugger.  I hadn't thought about it before but the head and upper fins have turned black.  Like I said before the engine is a good runner.  The insides appear almost new.   As always this was an eBay special I scored cheep.

Is their any reason that I can't shave the back plate till it clears the crank?  Also I will try and strip off the paint.  Can't be good for cooling.  Hay cheep is good when you can get it to run!  LL~
John Rist
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Offline Bill Adair

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Re: OS Max LA -15 back plate.
« Reply #4 on: September 15, 2016, 05:29:18 PM »
Hi John,

Check with Randy Smith, and/or Eric Rule at RSM, as they may have gaskets for the LA 15 back plates.

Just checked my NIB OS FP and LA 15 engines, but I don't see a gasket on either of them? I already replaced the plastic back plate on my LA, but don't remember if it had a gasket?

Something else may be causing your binding? Did you make sure that the thin steel thrust washer, is under your drive washer?

Also, let me know if you need a metal back plate.

Bill
Not a flyer (age related), but still love the hobby!

Offline Motorman

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Re: OS Max LA -15 back plate.
« Reply #5 on: September 15, 2016, 05:50:32 PM »
Sounds like it's been in a crash on the remote needle and warped the back plate? The plastic backplates I have don't use a gasket and don't rub. I put large area flat washers under the bolts and don't over tighten and no leaks so far.

Who was it that made all those metal backplates for the LA engines?


MM
Wasted words ain't never been heard. Alman Brothers

Offline Bill Adair

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Re: OS Max LA -15 back plate.
« Reply #6 on: September 15, 2016, 07:16:54 PM »
Think I got mine from Curtis Shipp.

Bill
Not a flyer (age related), but still love the hobby!


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