In article , "Morgans" wrote:

"Paul Smedshammer" wrote

The Mooney M20F has a fuel injection system so there is no carburetor nor
'carb heat'.

Paul

Right, I know it is fuel injected, but it is a "throttle body" type, rather
than individual injectors for each cylinder, isn't it?

It seems to me that if it is this type, a possibility of a temperature drop
from evaporating fuel could still open up an opportunity for water vapor in
the air to freeze, in the right conditions.

The IO-360A1A has individual injectors to for each cylinder. However, I'm
still learning about the potential for induction icing to occur and I think you
are right that this is a definite possibility.

But as somebody mentioned in another post, if induction icing were the cause I
should have seen a rise in the EGT as the fuel flow became restricted instead
of a sudden drop from 1310 to under 1000 F.

The most plausible cause that many have suggested so far is that there was
water mixed in with the fuel. When I enriched the mixture it let a larger
volume of the fuel/water mixture in which resulted in a slightly smoother and
more powerfully running engine. Which would also account for the lower EGT.
Then as this fuel/water mixture worked its way through, normal operation was
restored when the fuel/water mixture returned to just fuel. I really hope
this was the cause but I'm still open for it being something else that I need
to be aware of.

I still get sick thinking about this happening on climb out with a broken
cloud and fog deck at 800 feet. As it took about 8 minutes to clear at full
throttle in cruise there is no way it would have cleared during the climb out.
And what is worse, if it was water in the fuel, I could have sucked in a full
slug of water killing the engine completely. This was a serious learning
experience for me. Just glad I'm around to apply it.

Paul