I have tried to search through dozens of pages on this forum, and have yet to find a satisfactory answer to a problem that I am facing.

I recently had a 31c707-0230-e1 engine throw a connecting rod. After rebuilding it a half dozen times and never getting it to work, I finally found a replacement. I installed the replacement in a matter of just a couple of hours and it fired right up. However, there seems to be an excessive amount of smoke. There was less the 2nd time than the first time I ran it, and it appeared to happen more at lower throttle settings. There also continues to be smoke billowing out of the muffler for about 10 minutes after shut down. I've only run it a max of about 2 or 3 minutes at a time. Perhaps I haven't let it get to op temp so that the valves and piston rings set up. So here are a couple of questions that I'd like to bounce off the users here:

A) When I installed the new engine, the attachment of the throttle linkage seemed very subjective. Is there an accurate way to install the throttle linkage?

B) Is there a mixture adjustment screw that I can tweak while the engine is running at low idle so that I can lean it out?

First of all, I DID find cusser's solution to ensure that the choke reopened after dropping the throttle down from "Choke" to "Mow" speed. I will definitely look into doing that, as well as running carb cleanser through the throttle housing. I also know how to set the valve clearance and may need to do that.

Any additional help or information - particularly on things that I can set like screw positions, etc., would be greatly appreciated.

Thanks,

Jim