Hi David

Can you give a reference for the stats for carb-icing accidents?

Here is a quote fron Gene Whitt -

On average there have been 35 unexplained 'engine failures'
per year. Most of these have been Lycoming and attributed
to carburetor icing. Where POHs do not recomment heat unless
required, pilots lose the Continental sensitivity to pick up
on an unexplained rpm drop. Solution: Fly Lycomings as
though they were Continentals. The forementioned 35 are due
to complacency in the use of C.H.


Were you ground leaning as aggressively before the stuck valve as you
are now? If so, the more obvious explanation would be the leaning,
not the oil additive.

I was, but at that time I had a partner, so I cannot say for sure what he
was doing.
But the oil additive is cheap - and FAA approved. The valve job was
$650.00, so I see it as buying insurance.
I really don't want to try flying without it and then end up with another
stuck valve. That is probably why these guys sell so much additive -
people don't want to risk it

--
Tony Roberts )
PP-ASEL
VFR-OTT - Night
Cessna 172H