Yamaha 150 TXRC: Help Understanding DC Voltage readings

[boscoe99]

code 13 indicates something about one of the two pulser coils are not feeding information to the ECU/cdi.
lose one leg of a pulser and you lose one cyl,lose both legs on a pulser you lose spark on 4 cyl.
it is a simple system but I never understood why two pulsers and a CPS.

It is the Yamaha modus operandi. If X number are parts are required to do the job then Yamaha will use X plus Y parts.

More parts being used means more parts that can fail which means more spare parts sales. That is the only reason that I can think of for them doing what they do.

But then they come along and create a trim/tilt relay assembly (one part) to replace two parts (individual relays) contrary to their usual way of doing things. The assembly only costs 20 or more times what standard Bosch relays cost at the local auto parts store. When a relay assembly craps out on a Yamaha built but Mercury branded motor, Mercury offers a retrofit kit to do away with the Yamaha assembly and go back to using individual plug and play relays.

Have you ever wondered about the many different ways that Yamaha motors are designed? It is almost as if there is no one company mandated way of doing stuff. Appears to be maybe 10 different design groups all doing whatever in the heck they want to do.

I won't get into the Yamaha publications department that writes the service manuals. They are in never never land.

[dray0151]

Could you put one of the Mercury retro fits on a Yamaha?

[boscoe99]

Could you put one of the Mercury retro fits on a Yamaha?

Yes. Absolutely.

For example, here is the kit that Mercury offers if and when the relay assembly on their Yamaha made 115 four stroke craps out.

https://www.google.com/search?q=8827..._Vuym14EZUU0M:

[dray0151]

great to know I will bookmark this

[zenoahphobic]

I've come on this a bit late.

There's talk of all sorts of voltages.

The difficulty is using the same equipment used, or indeed understanding what the instructor or the instruction means.

We like things simple. But often things need to be observed in action. Static and one figure readings don't necessarily weed out a fault, or if indeed there is a fault.
Mentioned a while back, I threw out my old, heavy, blurry green vacuum tube oscilloscope. But I have not replaced it. There must be quite cheap, simple to use equivalent test equipment out there, that visually shows and also gives clear numeric information.

Cheap DVM's suffer from "false" display. Example: when measuring a Quad bike's ignition recently, I measured the coil output (spark) and got a very low voltage reading (I think it froze at several hundred volts, there was no spark at the plug). Then measured Ohms, no reading or infinity. This lead was indeed open circuit, it seems designed that way. Now why would you get any voltage reading at all, as nothing jumped a substantial gap, and there was no capacitive connection to speak of?.

it was the meter that was telling lies and wasting my time! DVM's suffer from sampling , averaging digitally and display guesses. A sensitive analogue needle meter gives a more accurate indication of the "value", but you need to convert what you see, unlike a digital display.

[Psalm 99]

Thought I’d summarize the testing data on the engine:
Pulser coils: Resistance: 306/307 ohms both coils
Peak voltage: 15 VDC both coils @ 1500 rpm
Charge coils: Resistance: Low speed coil – 750 ohms
Hi speed coil – 72 ohms
Peak VDC: Low speed coil – 248 @ 1500 rpm
Hi speed coil – 244 @ 1500 rpm
CDI Output: 200 VDC peak for to each of six ignition coils
CPS: Resistance – 196 ohms
Peak voltage: 10.5 @ 1500 rpm
The peak (measured with DVA adapter) voltages from all the units is quite high compared to the manuf. Spec sheet. However, I’m assuming the manuf. Spec sheet for peak voltages is the minimum required for design performance.
Coil resistance is almost exactly as stated in the manuf. Spec. sheet.
This morning the Winky-Blink showed a ‘normal’ code for the CDI for each of four runs on muffs (between 800 – 2700 rpm). A few days ago, I got both a ‘33’ code on engine start-up which lasted a few minutes and then reverted to a ‘1’ or normal code. However, that day, I also got periodically a ‘13’ code which indicates a faulty Pulser coil(s). From the explanation of the ‘33’ code, the 33 code is normal on engine start-up. But the ‘13’ code seems to pin-point the problem.
As mentioned, the problem is very sporadic. Engine may run for many days without problems or simply crash down to 1600 rpm after only a few minutes run-time. Taking the data’s been the same way: today all was good, a few days ago the ‘13’ code appeared intermittently. New pulser coils are expensive but that seems to be the way to go. Sure appreciate all your comments/suggestions.

[99yam40]

I would think connection more than a bad coil.

but it could be an internal connection I guess

My guess would be a connection you moved around while testing

[Psalm 99]

Problem has been on-going for some time but got worse over the last few months. First went after the fuel system and pretty much replaced/rebuilt everything. When the tach started to jump around after the rpm's crashed, I went back to looking at the electronics. The tach wiring looks like it gets its signal from the pulser coil(s) and with the winky-blink periodically showing a problem with the pulser coils, that's just about the only direction I have. Removed pulser coils and everything looked fine. Not much there to see. Wiring connections were strong; unit looked new. This engine only has about 600 hrs on it but this issue has been a continual on-again/off-again problem pretty much ever since I got it with only 325 hrs on it. I'd guess its simply a bad wiring connection but all I've got are the four wiring connections from the the two coils and the plug into the CDI. These are all good. Will post when the new pulser unit is installed but confidence in this expensive solution is not real high at this point. Thanks again to everyone for sticking with me on this.

[zenoahphobic]

On again off again problem for 275 hrs running over considerable time tends to discount an external connection failure, as the cause or nature of the faulty connection (looseness, corrosion) changes itself overtime leading to complete breakdown likely
So my bet it is an internal issue, that probably can only be solved with a replacement of a part. I'd be hopeful it's the pulser coil, if not then it would have to be within the CDI unit I would think.

[Psalm 99]

That's pretty much along the lines I've been considering. What little is known points to the pulser coils but the CDI unit may also be suspect. Still, this Yamaha engine is an extremely fine engine. Anytime you get something used you can pretty much bet on a few problems.

[rodbolt17]

all that code 13 is telling you ios the ECU is not happy with its inputs.
it is NOT telling you a pulser failed.
that is where testing while it has failed is nessasary.

[boscoe99]

That's pretty much along the lines I've been considering. What little is known points to the pulser coils but the CDI unit may also be suspect. Still, this Yamaha engine is an extremely fine engine. Anytime you get something used you can pretty much bet on a few problems.

The CDI is always suspect.

Yamaha loves when that happens.