Hobbs meter intermittent

[Flymu2]

I noticed a few flights ago that my Hobbs wasn't tracking my actual flight time. I had the mechanic look at it. He says no loose connections and good power to the meter. He also says that it's actuated by oil pressure, but the Hobbs time was keeping actual flight time, not engine running time. When I bought the plane it had two Hobbs meters, one on the panel and the one on the aft baggage compartment rear bulkhead. The one on the panel tracked engine time. I had it removed.

 

Questions:

 

What actuates the factory installed Hobbs?

 

The mechanic said Mooney referred him to a company in California that overhauls the factory meter. They want $2K to just look at it!!!!! Not an option. Any other sources for repair/overhaul?

 

Thanks,

 

Dennis Wolf

[PMcClure]

There was a service bulletin for tach generator replacement on the r model. Not sure about the eagle but it is the same engine. A $900 part will fix it. I had a post a few months ago. Pm me if you want the details. Its not the meter but the pick up on the mag.

[kortopates]

The factory Hobbs or hour meter, gets its input from your factory Tach/RPM meter which gets its input from a Hall effect sensor screwed into your left mag - although you didn't say what model you have. Usually the hour meter will work as long as the tach is working. When my tach went out I replaced it with a Digital E.I. R1 meter that fits in the same hole as my factory tach. Its TSO'd and STC'd to replace your primary factory tach and connects to your ignition switch making for an inexpensive install. see http://buy-ei.com/portfolio/r-1/ Under $450 from Spruce and EI will program it with your existing tach time.

Sent from my iPad using Tapatalk

[Flymu2]

There was a service bulletin for tach generator replacement on the r model. Not sure about the eagle but it is the same engine. A $900 part will fix it. I had a post a few months ago. Pm me if you want the details. Its not the meter but the pick up on the mag.

 

PM sent. Thanks.

[carusoam]

OK...

I think we have two things going on.

The long body Hobbs meter is on the back wall of the cargo area and hard to read from the pilot's seat.

It is electric, and what I remember, it is air speed activated. So it only counts hours while the plane is flying, and doesn't count while the panel is on during pre-flight. Not oil pressure activated so idle time is not collected.

I'm not sure why the tach generated would be involved. Off to the books to find out what I can read about it.

I have an early R, things may have changed...

Best regards,

-a-

Update.... From a O2 POH....

HOUR METER (NOT SHOWN)

Hour meter - located on baggage compartment bulkhead indicates actual flight time and is trig- gered by the airspeed switch. Location may vary depending on installed systems.

[PMcClure]

OK...

I think we have two things going on.

The long body Hobbs meter is on the back wall of the cargo area and hard to read from the pilot's seat.

It is electric, and what I remember, it is air speed activated. So it only counts hours while the plane is flying, and doesn't count while the panel is on during pre-flight. Not oil pressure activated so idle time is not collected.

I'm not sure why the tach generated would be involved. Off to the books to find out what I can read about it.

I have an early R, things may have changed...

Best regards,

-a-

Update.... From a O2 POH....

HOUR METER (NOT SHOWN)

Hour meter - located on baggage compartment bulkhead indicates actual flight time and is trig- gered by the airspeed switch. Location may vary depending on installed systems.

On My 2002 O2, there is only the tach located in the baggage compartment. Nothing on the instrument panel. I understand it is an actual tach, not a flight time meter. It is driven by the tach generator.  Not sure when it changed. 

[Awful_Charlie]

On My 2002 O2, there is only the tach located in the baggage compartment. Nothing on the instrument panel. I understand it is an actual tach, not a flight time meter. It is driven by the tach generator.  Not sure when it changed. 

 

My '97 Bravo is the same, but somewhere (in one of the Mooney manuals) it states that the hobbs counts when the tach is over (IIRC) 2000RPM, thus removing the taxi time, but including the runup check. I keep meaning to put a meter or LED on it to see when it cuts in and out, one of those jobs for another day