Do you know who rebuilt it? Some folks' idea of "rebuild" differs from what is correct. A sloppy cylinder boring/honing job will make it difficult for the rings to seat with the cylinders.
If it were mine, I would drive it on a road where you can safely work up to 50 MPH and let off the throttle down to about 40, and keep doing that over and over again. It's hard to tell how long you will need to do this to seat the rings. Too many variables.
The reduction of smoke is what you need to look for.
I have had two 235s completely rebuilt without cutting any corners and neither of them smoked or consumed oil.
I realize that your engine is a 250, but the same principal applies even with a push lawn mower engine.
Last edited by 52Carl; 03/10/2024 4:20 AM.
