1989-90hp- 2cyls no spark

[wfowahoo]

Have search and read many pages of NO SPARK

Trigger voltage should be 4vt, it's 2vt.
Trigger ohms should be 1100-1400 or 11 to 14.
my auto ranging DVM says 1.2 to 1.3 K ohms. Is this a correct reading?


Stator test

Blue lead to red lead (low speed) ohms should be3.6 to 4.2, meter says 3.39
Red stator lead t ground should be 90-140, meter says 104.9

Stator voltage
Blue lead to engine Grd=110 vts.
Red lead to Grd = 8 vts.

Top two cyl. no fire. Don't know how to interpret the info.
Thanks Tom

 

[water world]

Re: 1989-90hp- 2cyls no spark

go to cdi.com should help

 

[CharlieB]

Re: 1989-90hp- 2cyls no spark

Ohm readings are only a guide, #'s radically out of spec are cause for suspicion, your readings are within range, but are not necessarily reliable proof of your problem.

Peak voltage readings are also not reliable indicators of a problem, they too are unreliable.

DVA readings are the most reliable indicators, voltage reading while under a measured load.

Either a DVA meter or a DVA adaptor connected to your meter will give you reliable readings.

You can build a DVA adaptor quite cheaply using the directions posted here

http://forums.iboats.com/showthread.php?t=374544

Once you have the DVA adaptor, follow the directions in the CDIElectronnics free downloadable Ignition Troubleshooting Guide to positively determine your ignition problem.

Remember there is a minimum 300 RPM cranking speed, low trigger and stator voltage together may be a sign of poor battery cable/starter problems.

 

[wfowahoo]

Re: 1989-90hp- 2cyls no spark

Thanks for the response Charlie B,
I took a chance and replaced the switch box,That was the problem.
I have a DMM that can read up to 1000DC volts. Do I need a DVA? Is this for reading peak voltage at the coils? What other component will put out high voltage?

Thanks Again, Tom

 

[Texasmark]

Re: 1989-90hp- 2cyls no spark

Do I need a DVA?

Thanks Again, Tom

The DVA is basically a little power supply containing a rectifier diode, a storage capacitor and a bleed resistor.

The problem with ignition systems is that the spark plug firing voltage has such a steep rise time and short duration, with a relatively long rest period between pulses, most meters can't read the pulses.

The DVA converts the pulses to DC (rectifies them). The capacitor charges to the peak rectified voltage and holds it (diode helps to keep it from bleeding off back through the input circuit) and the resistor is in there to keep a little bleed current out of the capacitor so that it will follow the input, not charge up to the peak and stay there. Now the meter has a relatively flat dc voltage to record and present to you.

So, yes, you need the DVA.

Mark

 

[CharlieB]

Re: 1989-90hp- 2cyls no spark

A broken, yet abutted wire in a coil can measure both Ohms and generate a 'no load' voltage, however the moment any load is placed on the circuit the voltage drops to near zero, the limit of the poor connection.

A peak reading meter can only measure voltage.

Direct Volt Amp (DVA) imposes a measured load which forces the circuit to do more than generate voltage, but flow current, do a measured amount of work which will cause any 'poor connection' to become apparent by its failure to carry that load/current.

 

[wfowahoo]

Re: 1989-90hp- 2cyls no spark

Thanks for thanking me to school.I really appreciate your knowledge.
Should I build a DVA that can handle 1000 volts, reference in previous posts. Or

Found this one on Ebay,but only goes to 400 volts.

http://www.ebay.com/itm/Marine-DVA-..._Automotive_Tools&vxp=mtr&hash=item3a6d78b130

 

[CharlieB]

Re: 1989-90hp- 2cyls no spark

Somebody did a nice job building the one shown on ebay.

You could build the same unit using the directions in the link I posted for a LOT less, way under $10

 

[Texasmark]

Re: 1989-90hp- 2cyls no spark

I built mine out of old scrap electronic parts sitting around my shop.

Mark

 

[Texasmark]

Re: 1989-90hp- 2cyls no spark

I built mine out of old scrap electronic parts sitting around my shop.

Mark