Motor break in
 

What is the best way to break in a rebuilt motor?
Thanks, Jeff

It might depend on what motor you have but I think the either the service manual or owner's manual will tell you what to do with a NEW motor which I would think is about the same. I know you run it at 1/2, and full throttle light load, and under load. Someone will let you know shortly.

I brake in a new or rebuilt motor the following way:
The first 10 to 15 minutes I don't move the tractor and vary the RPMs.

The next 10 to 15 minutes I will drive the tractor around and vary the RPMs.

If everything is ok I will hook it up to my break in sled
http://i152.photobucket.com/albums/s...b_Dude/307.jpg
or find something to put a load on the motor. The RPMs are varied while the load is on the motor. I will drive it like I stole it.

After 30 to 45 minutes of having a load on the motor I will leave the motor cool down and retorque the head bolts. The motor oil is change at this time. The carb is fine tuned. I will double check all the bolts to make sure they are tight at this time. Most of the time I will hook the tractor up to the break in sled or a moldboard plow and drive it like I stole it for the next hour. Motor should be broke in by them.

After 5 hours of run time I will change the oil again.

My Son's 86 pulling 400 to 500 pounds.
http://i152.photobucket.com/albums/s...b_Dude/306.jpg
http://i152.photobucket.com/albums/s...b_Dude/305.jpg
My 149's motor had around 2 hours on a total motor rebuild when it went to a plow day and plowed "like I stole it" for the next 3 to 4 hours.

I haven't had one fly apart.

Broke it in
 

Thanks for the advice Merk, I didn't have a sled to pull so I tried out the plow I bought for it.
Here are some pics of it when I finished:Kohler1:

Great pics Jeff! You got the cub nice and dirty. :IH Trusted Hand:

Wow that's slinging some MUD Jeff! Great pics thanks for sharing!:Thanks:

Slinging mud
 

Scotty it was fun slinging some mud while breaking it in.
By the way I like your avatar.:buttrock:

Bill the engine runs great.
When I tore it down, I took it to one of my neighbors who has a engine machine shop. He said I was lucky that the po must had changed the oil regularly, because the bottom end was still tight. He told me that not keeping a clean air filter in it will wear out the top end. He boared it out .010" over, new piston and rings, lapped the valves, and removed the balance gears, and installed new oil seals ( the front one was loose just hanging on the front of the crank when I removed the engine).
No more smoking, oil dripping and plenty of power, it should be good for another 30-40 years.:Kohler1:
What a great little engine