Just got M20C back from annual

[Bryanmooney]

I jsut got my c model back from annual. Looks like for some reason, the manifold presure gauge is sticking. No real relation to an actual reading. Sometime stuck on 25 in sometimes on 20. Reving throttle up makes no difference. Have not talked to the AP yet, any ideas/ quick fixes?

 

 

[Z W]

When my gauge did it on the M20K, it was a faulty gauge.  Rebuilt for a couple hundred bucks, works great.

[carusoam]

From my '65C experience...

There is a bleed hole in the aluminum tube that can initiate a crack in the MP line. Any maint. behind the panel can accidently open it up.

Visual inspection of the tiny hole may result in an interesting solution. Searching this site may give the dimension of the tiny hole...

Good luck.

Best regards,

-a-

[BigTex]

Same thing happened to me and I had my mechanic blow out the line and its worked fine after that.

[carusoam]

It may be a good idea to have the line pulled out for cleaning. It will have the 100LL blue goo in it to some extent...

Best regards,

-a-

[Bryanmooney]

Looks like a day later it is still stuck on 24inches. AP says it is probably a gauge.

[jetdriven]

is it stuck at 24" with the airplane not running? 

[Sabremech]

Had it happen to me. Blew out the line and then purchased a new gauge. No issues since.

David

[N201MKTurbo]

The gage in my F did that once. It had a screw in oriface in the input port of the gage. I screwed it out and cleaned it and screwed it back in and everything was fine. If it is screwed in to far the gage will be slow to respond if it is to far out the needle will vibrate with the engine pressure pulses. Adjust it till the needle just stops vibrating.

Other designs have an internal oriface tube and will need to go to the shop.