If one drives the vehicle maybe 15~20 miles when the ambient is between 35 and 45 degrees and the atmosphere is foggy, then one will learn first hand while manifold heat is important. Inline engines tend to have more of an icing issue than Vee engines.

The above temperatures in a light rain will produce the same results.

Jon

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop