8 HP Briggs & Stratton thrown con-rod

[NormL]

OK. First off: I bought the Roto Tiller attachment for cheap, knowing the engine did not run. So what happened to cause that condition DID NOT HAPPEN UNDER MY WATCH. What the seller neglected to tell me was that the engine could not run. I found that out when I got the head off and discovered that only the valves moved up and down when I spun the crank.

In the first three photos you see the pieces as I found them in the crankcase. In the fourth I'm trying to show some of the damage to the crank. The fifth shows where the con-rod whacked the side of the crankcase and the bottom of the cylinder wall. Not too much damage there. I should be able to hone the cylinder wall enough to rub that out.

My question is why did this happen? There was enough oil in the engine when I bought it but the crank looks to me like the engine ran dry at some point and though the operator filled it again, the engine soon packed it in. If there are other scenarios, I would like to hear about them. Also, at todays' parts prices, does it make sense to overhaul this engine, or should I just wait for a good used one or even one of the cheap off-shore units that Princess Auto here in Canada has on sale from time to time?

Thoughts?

 

[RandyT]

Cause of failure is lack of lubrication, ie, not enough oil. due do cost of repair parts it is not worth repairing unless you really want something to do. I would look for a good used or new engine and not mess with this engine.

 

[Fixemall]

Some rods are really cheap others...not so much. As far as the crank goes, they usually clean up with a little muratic acid and 2000 grit. I did a mower last year on a bet that was worse than that and my buddy mowed all summer with it no problem.

 

[Craig Clayton]

I was given for FREE a Lawn Boy that a work buddy could not get working that he picked up on trash day. This was a good looking lawn mower. End of the story snapped connecting rod. I threw the entire mower in the scrap metal bin.

Another work buddy found the steel water shut off valve with his lawn mower, he twisted the crank.

Buy an engine equal to the length of time that you want it to last at PA.

Craig Clayton

 

[NormL]

I was given for FREE a Lawn Boy that a work buddy could not get working that he picked up on trash day. This was a good looking lawn mower. End of the story snapped connecting rod. I threw the entire mower in the scrap metal bin.

Another work buddy found the steel water shut off valve with his lawn mower, he twisted the crank.

Buy an engine equal to the length of time that you want it to last at PA.

Craig Clayton

That's about the size of it, Craig. The number of hours running time on a Roto Tiller will not be a whole lot on a yearly basis. Even if our plans for breaking up a few acres of grass for specialty crops comes about, there still should be lots of years in one of those units. One question: do you know if the motor mounts on those engines are the same as the B&S? That would help a lot for re-powering with other than original equipment.

 

[2458n]

Quality Farm & Fleet used to ship and sell without oil in the motor. Many had the piston stuck, beat loose ,oil added and then ran until they quit. If it still looked "new" or low hour this could have happened. Harbor Freight clone 6.5 might work.

 

[tcartwri]

I have a rod and piston just like this on my desk. It's from lack of oil.

They are splash lubricated, and if you run them low, or run them on an incline, they pop.

 

[NormL]

Quality Farm & Fleet used to ship and sell without oil in the motor. Many had the piston stuck, beat loose ,oil added and then ran until they quit. If it still looked "new" or low hour this could have happened. Harbor Freight clone 6.5 might work.

I'm not going with less than 8 HP due to the cement (clay) we farm in around here. If I decide to re-power it I'm looking at 10+HP.

 

[5030]

Get yourself a Honda OHV. It will outlast the equipment you out it on. Briggs are throw away engines like HF's Predator.

 

[oldballs]

Get yourself a Honda OHV. It will outlast the equipment you out it on. Briggs are throw away engines like HF's Predator.

That's bull****. The old B & S engines run as good as any. I know, because I'm running some today that are over 30 years old. Today's B&S I don't know that much about except that they make a top line and a cheaper line. If I live to be 110 years old, I'l let you know how the cheaper line runs.:laughing: