Briggs Crankshaft Gone Bad?????

#1
Hello everyone, I have a B&S 5hp flathead, that seized up do to lack of oil. if i put a pipe wrench on the keyed part of the output shaft the piston spin but not easily. I think I threw the bearings, since its a model tat uses bearings not bushings. But what is the possibility of the hardened shaft getting eating into by the bearings? the seizure was not an abrupt one it was like a slow down reving sound. also the piston walls are fine.
 

vette66_00

Active Member
#2
Hello everyone, I have a B&S 5hp flathead, that seized up do to lack of oil. if i put a pipe wrench on the keyed part of the output shaft the piston spin but not easily. I think I threw the bearings, since its a model tat uses bearings not bushings. But what is the possibility of the hardened shaft getting eating into by the bearings? the seizure was not an abrupt one it was like a slow down reving sound. also the piston walls are fine.
I would not think the shaft would not get as much damage as the bearing retaining area would. Since the block is made of aluminum I would think, if any damage other than the bearing it self, it would be on the block. Best way of telling is to take it apart and see whats going on. Bearings should not be to bad in price and a machine shop should be able to press off the old and press on new bearings.

I bet you will check the oil a bit more now. hehe
 
#3
I would not think the shaft would not get as much damage as the bearing retaining area would. Since the block is made of aluminum I would think, if any damage other than the bearing it self, it would be on the block. Best way of telling is to take it apart and see whats going on. Bearings should not be to bad in price and a machine shop should be able to press off the old and press on new bearings.

I bet you will check the oil a bit more now. hehe
HAHA!!! Sounds right to me.. Plus, the cylinder wall looks fine but I am willing to bet it is because the piston rings melted it like brand new before the piston welded itself to the wall... Your bearings are junk too. You might have a hell of a time getting that motor apart. It probably only has bearings in the back so if the engine had melt down I would say the front journal is probably not the most awesome part in the world either.. I had a 5 horse flatty seize but it's all aluminum and burnt out.. I got mine broke loose and she still rips... I need to get to replacing it though.. Right now after I send these boxes out to a couple Old Mini Bikes guys...
 
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