The Cessna 120-140 Association Forum

Next item on my list is addressing the VSI on the 140 panel. It's MVFR and descending about 100fpm
Any recommendations?

I’ve had good service from Rudy’s.

There should be an adjustment screw to stop the decent, probably hidden by the panel.

Looks like it's in a fog; dry it out?

Thanks for the adjustment tip John.

It looked that way since I owned it; approaching a month.
If I could access the back side of the glass it should be easy to clean/dry but I am guessing the instrument is sealed... I suppose I could try a hair dryer.

I don't think it's sealed; I think the case is connected to the static system. (IIRC, that's the glass to break when your static system ices over in IFR conditions.)

I used Aircraft Quality Instruments for my overhauls of the AS and ALT. Good service, but as John has suggested I think I would try and dry it out first. Maybe you have or could borrow someones food dehydrator and the make the adjustment with the screw John has indicated.

I've had good luck buying used VSIs on ebay. Before you take your current one out, take the one you bought with you on a flight with the port on the back open to check it out.

John, Blaine, Ray. Excellent suggestions.

Thanks for all the help and recommendations.