My Tractor Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
339 Posts
Discussion Starter · #1 ·
The other week I was chipping with my Super Tomahawk chipper ( early Troy Bilt ) and it's powered by a 8 hp Briggs.



The next thing I hear is screaching belt as the engine went suddenly silent. :Stop: I went to pull the recoil starter and it was jammed tight.

The next day I took the engine off, drained the oil ( yes , it was full. I always check oil levels before topping off with gas ) and noticed the drive pulley moved back and forth but the flywheel side was tight. That is a bad sign.

Here's pictures of the carnage.




Seems the crank decided to seize in the block on the flywheel side and shear off.

I did find another 8hp briggs off a rototiller that I picked up for $75.

I just rebuilt the Kohler K-301 in my Cub Cadet 125 and after comparing it to this briggs, the briggs are junk.

Jeff
 

·
Premium Member
Joined
·
5,747 Posts
I don't think that seized in the block, as the bearing is not discolored. Remove the broken piece and look at the bearing. If it's OK, as I suspect, put a new crankshaft in it and go. I've seen Briggs engines break cranks on leaf blowers, but never in that location. If I was a betting person, I put odds on a out of balance flywheel. The chipper will not have the power to twist the shaft in two, as once the engine becomes the load, the belt will become slack, as the idler pulley will now be on the loaded side of the belt.
 

·
Registered
Joined
·
339 Posts
Discussion Starter · #3 ·
I don't think that seized in the block, as the bearing is not discolored. .......
Bearing? All B&S did was machine a hole in the block for the crankshaft to go thru. Aluminum block with a hole in it. I had to hammer the end of the crank out of the block.

The straight portion of the crank that the crank bolts to is where it snapped off. The "metal mites" chewed up the block pretty good.
 

·
Registered
Joined
·
6,227 Posts
I just rebuilt the Kohler K-301 in my Cub Cadet 125 and after comparing it to this briggs, the briggs are junk.

Jeff
You can't really compare those 2 engines. One is a castiron engine made to last and the other is a cheap aluminum engine not made to last. Big different's in price.
 

·
Registered
Joined
·
334 Posts
A little late, but maybe worth a mention...Couple of weeks ago I replaced my 8hp Briggs with the Harbor Freight 11hp. Had to fab a support for the base, since the Briggs is hung from the top, and modify the clutch bracket for clearance. Aside from that, a clean swap...and what a difference in power! A different machine altogether :bannana:
 

·
Premium Member
Joined
·
8,842 Posts
I have seen many types of failures on shafts. That crankshaft failed all by itself. If the bearing had seized and twisted the shaft in two it would have been a clean break. The jagged part is the clue.

I believe the cause was metal fatigue caused by a defect in the steel.
 

·
Registered
Joined
·
339 Posts
Discussion Starter · #8 ·
I have seen many types of failures on shafts. That crankshaft failed all by itself. If the bearing had seized and twisted the shaft in two it would have been a clean break. The jagged part is the clue.

I believe the cause was metal fatigue caused by a defect in the steel.
There is no bearing or bushing. Just a hole in the block where the crank went thru.

I got another 8hp b&s off a rototiller and other than having to make a bushing so the oil seal would actually touch the crankshaft, it was a simple bolt in.
 
1 - 8 of 8 Posts
Top