Tach increase?

[10musketeer]

Today while running errands, on about the 4th time I started the car, the tach stayed at zero. I tapped the glass (patented pilot trick) and it sprang to life. The only problem was it was about 1000 RPM high. It seemed to always be about 1K RPM high for the rest of the day and jumped back and forth about 1500 RPM while the engine was running steady during cruise.

What gives?

 

[DrEntropy]

Sounds like a patented aircraft trick... faulty instrument. Also you may want to check your points gap.

 

[bugimike]

Electric or mechanical??

 

[10musketeer]

electric tach, new (4 months), new cap and new coil.

Come to think of it, you may be right about the points gap. I do hear a slight, occasional miss that corresponds with the tach jumping. hmmmmmm.....

 

[Bugeye58]

Come now.... "Always trust your instruments". At least at night, in weather! /bcforum/images/%%GRAEMLIN_URL%%/grin.gif
Jeff

 

[DrEntropy]

Yeah, Jeff. I know, I know... Never saw any avionics with SMITHS on 'em tho.


...oh, waitaminit... /bcforum/images/%%GRAEMLIN_URL%%/blush.gif

 

[10musketeer]

oh man I have so many stories- Good thing most everything is redundant in an airplane. Maybe thats my answer- two of everything. Of course that just means I'd have one broken one and one good one for the moment. Sure look cool though! /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

I think I'll check the points first.

 

[DrEntropy]

/bcforum/images/%%GRAEMLIN_URL%%/thumbsup.gif Good 'alternate', John.

 

[dklawson]

You've never heard of Smiths aircraft gauges? I run across them periodically on eBay. They are out there.

 

[racingenglishcars]

If you had two sets of gauges, I'm afraid that would mean two sets of broken gauges.