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Old Jul 29, 2014, 12:08 AM
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United States, IL, Wheaton
Joined Sep 2013
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Magnum .91 FS. Damaged?

My almost new Magnum .91 four stroke took a hit from a loss of control on the downline of a stall turn. It hit hard into the dirt, burying the spinner. The engine was quickly inspected by some guys at the field. They agreed it is making a ticking sound upon rotation of the prop and that this means the valves need adjusting. The crank seems straight and no dirt entered the rear intake. It is ostensibly clean and in good condition.

I'm concerned that my almost new (break-in plus 5 flights) engine is damaged. How can I know if that's all that is the problem? Would running it damage the engine?

I appreciate your advise.

PD.
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Old Aug 01, 2014, 07:53 AM
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Lumpy05's Avatar
United States, IN, Bloomington
Joined Jan 2012
332 Posts
You should have an "engine guy" go over the engine before you run it. The valves could be knocked out of adjustment or just plain damaged in some way. The bearings could be damaged, etc.

Valve adjustment is fairly easy but if you have not done it have someone with experience show you how. You could take the valve covers off and turn it over by hand and see if you can find the source of the ticking.

Depending on what is wrong or not wrong with the engine you could have a serious backfire, cause further damage to damaged parts, poor or no running, or smooth running. There really isnt any way to know via the web.
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Old Aug 01, 2014, 02:33 PM
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United States, IL, Wheaton
Joined Sep 2013
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Thanks for the reply. I'm wondering if the sound is just normal, but previously unnoticed clicking. I'll take your advice and bring it to the field for an inspection before running it.

Thanks,
PD
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Old Aug 22, 2014, 03:41 PM
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United States, NY, Eldred
Joined Jun 2012
609 Posts
If the clicking wasn't noticed before, than I'd definately open it up to make sure everything is ok. Some four stroke valves make noise whe others are very quiet. Just as an example: O.S. And Saito four strokes you can barely hear the valve train movement, but on Thunder Tiger four strokes you'd swear something is broken.
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Old Aug 30, 2014, 11:20 AM
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United States, IL, Wheaton
Joined Sep 2013
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Update: I adjusted the valve clearances, and took it to the field. The clicking was similar to an OS 70 Surpass 2 that I have, so I thought I'd try it out. It runs perfectly. Smooth, long idle, crisp transition, strong top end. Thanks for your suggestions.
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