rattling noise from 12 hp 1989 briggs

[J. D. Ward]

What all could cause this? How would I know for sure? Model 281707 Type 041501 Code 9003143. I used fresh gas, new SAE HD oil, fuel filter, rebuilt carb ,cleaned head and top of piston.(Carbon) New gaskets on head, carb, and muffler. The valves seemed to be working ok. The engine runs pretty smooth, except for it has a rattle. Not a ticking like a lifter. At a lower idle, its not as bad. Speed the engine up the rattling sounds pretty bad. Can you help me out. Thanks

 

[chance123]

It could possibly be a rod. A way you can check this is to get a long small screwdriver, insert it into the spk plg hole and rotate the crank until you feel the piston about half way of its travel up or down in the cylinder. Then paying close attention to your screwdriver contacting the piston, slowly rock the crank shaft "just a little" back and forth. If you feel a moment of no movement on the screwdriver/piston, while the crank "does" move, you have excess clearance in your rod/crank pin. This is NOT an exact precise way of doing it, but it will allow you to check for wear/play.

 

[oldgrasscutter]

I have a 09 12.5HP Briggs that does the same thing. It has done it since it was brand new. Its like there is something loose inside. I've taken the engine cover of, tighten everything to no avail. It runs great and i have 250 hrs on it with NO problems. It is a mystery that I hope someone can figure out.

 

[Bison]

Check the the engine air cowling and the shields for being tight,a loose bolt somewere can cause a good rattle.
Mebbe the mufler has something ratling around inside?.

 

[Rivets]

Ward, I agree with chance, it's probably the rod. The engine is 22 years old and I would continue to use it as is.