Mitchell Tachometer - Need one ASAP

[sdflysurf]

Hey all, my Mitchell Tachometer D1-112-5025 is acting funny.  Checked the cable and that seems fine.  When I rotate the (not sure what to call the part - connector? spinner?) the hand on the tach moves, but it sticks in certain spots....like a spring isn't working properly to dial it back to zero.

Suggestions on if this can be easily repaired OR does anyone have one they could sell and overnight ship?

[Oldguy]

@Alan Fox or @acpartswhse might be two sources.

[sdflysurf]

8 minutes ago, Oldguy said:

@Alan Fox or @acpartswhse might be two sources.

Ok Thanks!  I also found @Frozen Flying had one in the avionics classifieds - hoping he still has it.

[gsxrpilot]

1 hour ago, sdflysurf said:

Hey all, my Mitchell Tachometer D1-112-5025 is acting funny.  Checked the cable and that seems fine.  When I rotate the (not sure what to call the part - connector? spinner?) the hand on the tach moves, but it sticks in certain spots....like a spring isn't working properly to dial it back to zero.

Suggestions on if this can be easily repaired OR does anyone have one they could sell and overnight ship?

The model, year and engine of your Mooney will be important. The markings on the face are specific to the plane. So to find a used one, you'll have to get one from the same model/year/etc. I did this twice in my M20C before giving up and getting an EI R1 electronic tach. But it takes some time as it has to be programmed to your POH.

[Steve W]

Actually, it's not just the plane, but also some engine or prop changes. When I bought mine a sharp eyed pre-buy noticed the tach was not re-marked when it was upgraded to a 3 blade prop. When I sent the documentation to JPI to program the 900 I had to include the STC for the prop as well.

[sdflysurf]

5 minutes ago, gsxrpilot said:

The model, year and engine of your Mooney will be important. The markings on the face are specific to the plane. So to find a used one, you'll have to get one from the same model/year/etc. I did this twice in my M20C before giving up and getting an EI R1 electronic tach. But it takes some time as it has to be programmed to your POH.

I think that the D1-112-5025 guts are all the same, but the markings are what need to be different - Is that true?  If so, mine has the red at 2100-2350 and then redline at 2700.

[sdflysurf]

I spoke to Mitchell just now and they confirmed - as long as the model number is the same then it will operate properly for my aircraft - just the markings are specific per the POH (prop and engine combo).  I'm on the lookout for that D1-112-5025 in good working order to get the plane in the air, while we have ours overhauled for a flat rate of $165.

[N201MKTurbo]

I never had good luck with Mitchell tachs. 

Go buy an electronic tach and all your problems will go away.

[sdflysurf]

5 minutes ago, N201MKTurbo said:

I never had good luck with Mitchell tachs. 

Go buy an electronic tach and all your problems will go away.

Question for you on that: What are the instructions for how to wire up (where to wire to) the Digital Tach and what to do with the Engine RPM cable?  Is it pretty easy?

[N201MKTurbo]

38 minutes ago, sdflysurf said:

Question for you on that: What are the instructions for how to wire up (where to wire to) the Digital Tach and what to do with the Engine RPM cable?  Is it pretty easy?

It depends on the tach. Some have a pickup that attaches to the engine where the tach cable goes. Some have a sensor that replace one of the cover plugs on the mag and some connect to the P leads, usually at the ignition switch.

You can buy a cover for the tach drive on the engine or make one by cutting your old tech cable in half and take the nut that screws on the engine and cutting a circle of sheet metal that fits in it.

If you get the ones that have the sensor in the engine compartment, you can route the wires through the grommet the tach cable went through.

Edited November 1, 2018 by N201MKTurbo

[jetdriven]

2 hours ago, N201MKTurbo said:

I never had good luck with Mitchell tachs. 

Go buy an electronic tach and all your problems will go away.

I second that. I bought a new one and it broke on the taxi out.  The repaired one was reading off 150 RPM.  I put in an SLI tach and fixed it. 

[sdflysurf]

OK - update - I found one from an avionics company that was kind enough to ship it out today for a very reasonable cost.  That will fix my immediate problem, but I am looking closely at the EI Digital Tach for a more permanent solution!

Thanks all!

[carusoam]

Nothing like losing engine instruments... like MP or RPM...

At least your smart phone can measure rpm based on sound, in a pinch.

Get a tach app before you need it.

PP thoughts only, not a mechanic...

Best regards,

-a-

[Spurious Moppet]

Well I see you found one. I think I do have one still just in case anybody needs it.