Cold engine surging

[Firespooks]

I have a 38” Husqvarna lawn tractor with a 18 1/2 HP B & S on it. When it is cold out side and I start it , the engine surges until it is warmed up. Then it runs smoothly. Is this normal ? Or should I be maintaining something ?

 

[ILENGINE]

That is actually normal especially with the newer EPA mowers because they run too lean when they are cold.. I have seen several newer engines that won't even start below 50 degrees without outside assistance.

 

[Auto Doc's]

Does it have a manual choke or automatic?

 

[Firespooks]

Does it have a manual choke or automatic?

Manual

 

[slomo]

When it is cold out side and I start it

What temp in F are you calling cold?

 

[Firespooks]

Around 50 degrees.

 

[Craftsman Garage]

Well, when you think about it, it actually makes sense, similar to what ILENGINE said. When air is cold, it is more dense, thus the engine actually pulls more air in with the same stroke. The fuel mixture stays the same whether cold or hot. So it runs lean for a little bit, but it's normal and nothing to worry about. If it has manual choke, you could pull the choke out more when running cold to even out the mixture.