Icing

[city998]

Topical in the current weather.
Has anyone experienced carburettor icing recently? I have a 998 with Stage 1 kit meaning the air pre-heater is gone. My engine runs fine at speed but I sometimes notice a slight throttle lag after a long high speed run when I let the revs fall. I suspect carburettor icing as it happens only on cold and damp mornings and when it stalled once just as I was parking it, it immediately fired up on restart so I reckon the heat in the engine melted the early icing. Anyone else?

[The Marcos Graveyard]

A water heated manifold would help cure this problem.

[woody]

I'd suspect the damp more than the icing if the engine is warm.

[city998]

Thanks for replies but I do have a water heated manifold. Due to the carburettor-to-manifold insulating spacer and the manifold being downstream of the carburettor, this does not help prevent icing in any significant way. What’s needed is heated inlet air. It isn't dampness in the ignition system as it only happens when conditions are just right (cold [u]and[/u] damp). I was just wondering if others have experienced the same thing. We normally don't get enough days with this condition to make it worth worrying about so I'm not engineering a solution just yet!

[woody]

Is she running lean?

[city998]

[quote="woody"]Is she running lean?[/quote]
Not overly. It was tuned to pass the NCT a few months ago but it usually gets richer as time goes on and the symptoms weren't there until the recent cold/damp conditions of the past couple of weeks.