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B&S 12Hp Engine re-build Questions


Hondal's Avatar
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06-18-07, 03:58 PM   #1  
B&S 12Hp Engine re-build Questions

Got my 12 HP Briggs and Stratton engine back from the machine shop. The Model # is 282707-0116. The engine was bored 0.020" over and I had the valves re-done at the same time. Based on the book i was following the orientation of the rings on the piston does not matter so I offset them so the gaps won't line up hope this is ok.
1)The question I have is the gasket kit has 5 different base gaskets to be used and from what I read it is to adjust for crankshaft end play but I can't find how to measure this on this engine cause once I install the base over the crankshaft I won't be able to access the crankshaft to measure anything. How important is this
2) Is the spring washer that fits between the govenor assemble and the camshaft required? This little washer spring fits between the case the camshaft.
I am waiting a call from the shop cause they forgot to give me the Govenor/choke arm that fits bewteen the carb and the govenor arm.
Any other tips is helpful.
Thanks

 
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06-18-07, 06:25 PM   #2  
The ring end-gap stagger is exactly as you should do and furthermore, keep the end-gaps from in line with the piston pin. Crankshaft endplay is determined using a dial indicator set up so that you can measure the parallel movement of the crank externally on the PTO (power) end of the engine. Generally, you will want between .002" and .008" of crankshaft endplay and if you have a good feel for this measurement you can do it by feel rather than finding and using a dial indicator. As for the "washer" you have, I've NEVER seen such a wave (spring, as you put it) washer used here or anywhere in the crankcase, for that matter. The Briggs website parts break-down for your particular model and type engine shows no such washer and assembly is shown - and known by me - to be camshaft then governor assembly then side (sump) cover.

 
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06-18-07, 07:46 PM   #3  
I also have never seen any washer used at the governor, camshaft, or any other thrust surface in the engine. I don't reccomend using one.

The gasket and sump cover must be in place and the bolts torqued before endplay can be measured. As Puey61 said, a dial indicator or an experienced hand can be used to tell when the endplay is acceptable.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
Hondal's Avatar
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06-19-07, 03:34 PM   #4  
Thanks to all. I thought the washer was missing cause in the four cylinder repair book they show one but maybe for another model. It looked like i need it but it is not in the illustrated parts list. To note the woodroofe key for the flywheel is not shown in the parts list so small parts might be missing from the parts list I am not sure. If you know the size of the woodroofe key for the flywheel that will help cause the machine shop did not provide that.

Thanks
Al

 
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06-19-07, 05:24 PM   #5  
The flywheel doesn't use a woodruff key. It uses a specially made flywheel key. This key is made to shear instead of break, or bend, so that it will not cause engine damage or fracture the flywheel if the engine comes to a sudden halt. Don't use a steel key, or the flywheel could explode in the event of sudden engine seizure. Any small engine shop should have the flywheel keys, and I think lowes, tractor supply, and other stores sell the keys in their lawn mower dept.


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God bless!

 
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06-19-07, 05:56 PM   #6  
The flywheel key is part number 222698S.

 
Hondal's Avatar
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06-22-07, 01:28 PM   #7  
Thanks all I got the proper B&S key and yes it is made of aluminum I think so everything is cool thanks again.

Cheers
Al

 
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06-22-07, 04:25 PM   #8  
Your welcome and yes, it is aluminum.

 
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