Yamaha f80 2003 4 stroke sigal only on one ignition coil wire

[primzy]

Hi,
I have a huge problem finding out what is wrong with my motor.
When I was checking timing on engine I noticed that i get signal only on one wire on each ignition coil.
Changed ignition coils and its the same. When I plug strobe light on wire cyl#1 stribe light blinks like it should. When I plug it on #4 it blinks very inconsistant or better to say ot doesnt blink at all.
Same story happens with second coil. Only get signal from one wire and its always upper one.
Please help, because it is killing me.
Problem is that engine starts to stutter at 4000 rpm. By giving a bit more gas it revs till 6300. Thats out of water.
In water engine could not go over 4000
Many thanks

 

[primzy]

I have already changed stator, cdi, 2x ignition coils with wires, spark plugs, throttle position sensor, complete fuel lines with 2 filters, pressure test fuel pump, checked compression, cleaned carbs, fresh fuel. Carbs are synchronized.

This engine is killing me. It ruined 3 trips to sea and its in good way to ruin 4.

On Video you can see test that bothers me. Blink of strobe is Hard to se. It appears as some rainbowy disturbance. 1. And 3. Cyl. Blinking as it should, 2.and 4.no blinking.

This video shows stuttering st 4000 rpm. Out of water, by giving more gas, after 4000 rpm, revs till 6200 like crazy. In water cant get above 4000

 

[boscoe]

When you use the word "signal" what do you mean?

Revving a motor in neutral or out of the water in gear means absolutely nothing.

 

[boscoe]

Do you have a Yamaha F80 or a Mercury four stroke 75?

 

[primzy]

Do you have a Yamaha F80 or a Mercury four stroke 75?

When you use the word "signal" what do you mean?

Revving a motor in neutral or out of the water in gear means absolutely nothing.

By signal I mean momental electricity traveling to sparkplug dont know how to call it...
Yes I know it means nothing, but if it doesnt run OK out of water, probably it will not run in water as well.
What gave me away
Yes, it mercury, but engine is same as in yamaha. I wrote here because I did not get any good advice at mercury section.

 

[boscoe]

Have you tested the CDI outputs to the ignition coils?

You have some connections and a ground to contend with. Have those been checked?

Has the battery power to the CDI been checked?

This from a Yamaha service manual.

 

[primzy]

I have tryed to measure output voltage on blck/wht and blck/orng wire, but with multimeter is imposibile. I think I need an ocsiliscope to se peak voltage, because its duration.
Ground wire goes with this two mentioned wire? If so, its fine.

Battery was fully charges so I did not consirn that. Definitely goimg to check if there is some unknow resistance.

I am mechanical engineer and I am ashamed that electrical shemes are not my strong part. I will get help from my frend Who does understand
I have manuals from mercury and there is nothing about how high should output voltage be.
I assume that there should be something with that, not enough voltage to produce 2 sparks. What bothers me is, I thought voltage would be seperated 50:50 to both wires from ignition coil. Apperently its enough power just for one...

Many thanks for your post! First one that made me think something new.

 

[primzy]

Ok, I found infos about peak voltage and its different!? Hmm, confused again.
Anyway I will try to measure it...

 

[primzy]

Have you tested the CDI outputs to the ignition coils?

You have some connections and a ground to contend with. Have those been checked?

Has the battery power to the CDI been checked?

This from a Yamaha service manual.

Can you please upload foto of number description (what is what).