which Volt Ohm meter should I believe?

[cropduster21]

I'm testing the charge coil under the flywheel on my 1995 15 hp 4 stroke manual start Evinrude. The motor has an intermittent spark problem hot days it generally shows no spark (using spark tester) cool evinings it shows spark. I have been suspecting the power pack. Today however, I thought I would test the charge coil again.(BTW. today its cool and damp in the 60s and there is no spark).

let me say that all of the cranking tests on the stator coil show that its in spec in resistance and the output is over the 100 volts minimum from the coil measured between both orange leads.

My manual says there should be no voltage between the orange leads from the coil to ground. My $40 digita craftsman meter shows about 18-30 AC volts going to ground when cranking. My analog (needle type) meter shows no voltage at all, even on the lowest scale. This same meter shows voltage is above the 100 volts minimum output of the coil between the two orange leads.

Which meter should I believe?

I need to get this motor running again and I dont mind paying a hundred bucks for a new charge coil stator. A new power pack is $369! I dont want to buy a new pack only to find out the stator is bad

 

[Faztbullet]

Re: which Volt Ohm meter should I believe?

Trust the analog unless the digtal has the dva adapter.

 

[Vic.S]

Re: which Volt Ohm meter should I believe?

For what you are doing the analog meter will be the more suitable instrument to use.

That's not suggesting that there is anything wrong with the digital one, Just likely to give the sort of readings you observe due to their very very high impedance.

Keep the digital meter for tesing electronic circuits ... that's where their high impedance becomes advantageous.

 

[JustJason]

Re: which Volt Ohm meter should I believe?

You need a meter thats shielded against RFI. If you have cheap (ie 40 dollar meters) I doubt they are shielded.
You also need a DVA adaptor to test anything ignition or charging related on most outboard ignition systems. You can get one of those through Rapair, ES (electronic specialties) or through your dealer. The only 2 meters I know of that have a DVA actually built in are the ES530 analog meter and CDI makes a DVA only analog meter.
I have a $500 Fluke meter and I have to use a $100 Snap on brand DVA adaptor on top of that. I get accurate readings each and every time.

 

[cropduster21]

Re: which Volt Ohm meter should I believe?

Thank you all very much. I had no idea about the dva adapter. My annalog meter shows the coil to be good . Ive already installed a new ignition coil (cracked) I guess I will have to start looking for a power pack. CDI tech support told me that they dont service my engine?? guess my motor is not cost effective for them to deal with. I sure wish I could find one cheaper than $300 (ebay)

 

[jonesg]

Re: which Volt Ohm meter should I believe?

the DVA is 3 parts, a diode,a resistor and a capacitor,
get all the parts are ratshack.

So simple it doesn't need a circuit board.
http://forums.iboats.com/showthread.php?t=299903&highlight=dva

or buy one (DVA adaptor) for $25

ebay has the complete marine meter for $65.
Search ebay under "peak reading marine meter."