Should my 18.5HP OHV surge when cold?

[Psychlopath]

I recently got my very first OHV Briggs and fit it onto an old Snapper rear engine mower. There's a thread on it here: http://www.lawnmowerforum.com/showthread.php/36983-Dumb-repower-questions

Part number for the engine is 31p7770348e1 and supposedly it has about 10 hours of run time on it. I had to replace the cam shaft, but I've done 4 mows with it on my more-or-less 1 acre plot and it's been fantastic.

The over head valve engine starts up easier than any of the old L-head engines I've had and I love it! It's also quieter and doesn't rattle my teeth out as much as the flat heads did.

Anyhow, my question:

When cold, the engine surges. As soon as it warms up a few minutes, it's very smooth and steady at any throttle setting, but I'm not sure that it SHOULD surge when cold.

I've adjusted the valves according to the maintenance manuals I've found online and had to adjust the high speed to get it into specs, but I don't know if it's normal for a few minutes of surging.

Maybe it's just how these engines are?

Can anyone tell me if cold surging for a few minutes is anything I should be looking into?

 

[ILENGINE]

It is not unusual for the newer engines to surge when cold. They are set to run lean to meet emissions standards, but isn't rich enough to run properly when cold. I wonder if the big push for the automatic heat controlled chokes isn't due to the running issues when cold.

 

[Psychlopath]

It is not unusual for the newer engines to surge when cold.

This is what I was hoping to hear.

Thanks!! Sounds like life is good with this new engine!