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12Hp Briggs And Stratton Knocking


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#1 MR Simplicity 6111 OFFLINE  

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Posted May 06, 2013 - 01:13 AM

Hello,

 

My 12hp B+S has a knocking noise that emits from the engine when given more than 1/3 throttle, there is no

knocking noise in the lower RPM range, only higher rpm. What could this be? My thoughts are that it is worn bearings.

 

Thanks



#2 MH81 ONLINE  

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Posted May 06, 2013 - 04:53 AM

I am thinking worn bearings too, might check valve clearance tho.. If rod, i would assume the noise would be there all the time. My FIL had a low speed knock on his Cub rider... Ended up all 4 bolts holding the engine down were loose.

Edit: anything out of whack with the shaft drive? Something out of balance at low RPM's?
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#3 pharmer OFFLINE  

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Posted May 06, 2013 - 05:35 AM

Mine did that on my 212-5 Wheel Horse and next thing I know the rod was in pieces and a hole through the case. I had the case welded and rebuilt the motor. Been using it for the past two years. You may want to check the rod now before a simillar event takes place. Welding an oil saturated case is not an easy task.
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#4 New.Canadian.DB.Owner OFFLINE  

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Posted May 06, 2013 - 06:59 AM

Is it a Syncro-Balanced unit?  I've had the syncro bearing wear out and I've had the dog bone break.  Both will give you an evil knocking.


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#5 MR Simplicity 6111 OFFLINE  

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Posted May 06, 2013 - 12:26 PM

I will check all bolts are tight, and it is smooth when idling. As MH81 said i wouldn't think it would be a rod waiting to be launched out the engine because it is only at a certain rpm range., and yes, it is syncro - blanced. 

Cheers for the help


Edited by MR Simplicity 6111, May 06, 2013 - 12:27 PM.





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