9.9 timing issue

Hi all, my 9.9hp, Yamaha 4 stroke for a number of years would only go to 3500rpm then after say 5 minutes it would go to full revs, approx 4600-5000rpm and not miss a beat until cooled and started again.
Now the fault comes and goes regularly after it has warmed up.
I have tracked it down to the timing not advancing, or the low revs are there when it hasn?t advanced and full revs when it does.
Unsure how low oil pressure is supposed to limit revs to 2000 but the oil pressure switch is working and indicating pressure via the LED at the console. I have shorted the wire to earth which is supposed to limit revs to 2000 but this does not happen.
So far it looks like a fault CDI. I have disconnected the trigger coil and motor stops.
Does anyone have any thoughts on what may be the problem, a new CDI in Tasmania where l live is $500 Australian which is ok if l replaced unit and it ran correctly but not if it?s something else.
Have checked all connections including earth on unit and all seem ok.
Appreciate any thoughts on this problem.
Regards, Kevin

Re: 9.9 timing issue

It will probably help if you state your motors model #.
I am sure it is 4 stroke as you speak of oil pressure, but what year is it.
Model # will give info. Newer motors the timing is controlled by CDI, but no idea what motor you have.

What is the timing during problem and without problem? Just saying it is not advancing does not help as much as #s
Check/test overheat alarm and safe mode also to see if it is functioning properly retarding timing and sounding buzzer.

If it was safe mode you would not get to 3500.

A service manual and the proper test equipment should be used to test all inputs and out puts before buying parts to make sure what the problem is

Re: 9.9 timing issue

Hi the motor is a four stroke as stated, 96 model, F9.9AE.
The timing is either 5 degrees at idle running well or not and goes to 35 degrees when running correctly or 5 when not advancing.It looks like there is only the 2 settings.
The model is a CDI advance unit as much as l can tell as their is nothimg mech to alter.
I have a service manual but the voltage tests aren?t to spec even when the motor is running correctly.
There is no overtemp or any other protection lm aware of apart from the oil pressure switch, which as said does not limit motor too 2000 revs as when motor is running correctly the motor will go to max revs.
Was after any other options as it all points to CDI, but maybe someone has other possibilities.
Regards
Kevin

Re: 9.9 timing issue

I would think something has to tell the CDI what the throttle position is so it knows when to advance the timing if it is controlled by CDI. Is there anything attached to throttle linkage that would move the timing mechanically or move something else that is hooked to CDI.

35 degrees sounds kind of high, but maybe that is what it is suppose to be at WOT. I am sure your manual gives the specs.
Speaking of specs what were the readings that were not in spec and if they were the peak voltages into and out of CDI ,did you use a peak reading volt meter or even a DVA adapter to read them? Specs are minimum voltages and normally read higher .

On my C40 there is a wiper on the cdi that the throttle linkage is tied to, something like (TPS) Throttle Position Sensor on other motors that is separate from CDI. The internal wiper had problems and messed up the idle timing but the WOT timing was fine. I had to replace the CDI to fix it.

Re: 9.9 timing issue

Hi Captain, thanks for the reply again. This may sound quite descending but I?m a very experienced electrician, have built a steal yacht including everything like the mast through to even bending the helm wheel through to rebuilding the diesel, sailed 10,000 miles solo, repairing my mistakes as l go. Have built total by myself a 330 m2 2 storey house. Not with standing numerous cars and motors, so l posted the question re- timing, thinking someone would ask silly questions, that l had answered in the initially thread and you did not let me down.
But what is WOT?.
Now after my spiel, l apologies because you are being helpful, but l understand motors and outboards and this motor has no other intelligence apart from stated. Did telling the model year not help you?
No visible throttle mech to advance timing. Manuals tell very little and if l believed what they said, the CDI, the pulser/trigger coil/ high voltage coil need replacement. Guess what, that?s everything. Even when the motor is running correctly. I believe it?s the CDI due to reasons given in other replies, but was hoping the guru himself (Rodbolt) may have answered. I could answer most threads on this forum with my knowledge, but l find it amusing that people with it seems limited tech knowledge answer threads that seem way out of there league.
Let?s start by me explaining how a cdi unit fires the sparkplug.
To be continued if anyone is interested
I know I sound nasty Captain, but I?m not, please type an answer to little old me in Tasmania.
Regards
Kevin

Re: 9.9 timing issue

Well if you are waiting on Rodbolt ,good luck.
if you care to look up the last time he posted, you would see he has not posted in a long time and does not even visit this site anymore from what he has told me.

If you have used the proper test equipment to take the reading from charge coil, pulsar coil, and the output of the CDI and they are not in spec. like you said, then it would not spark properly in my opinion.
But since you will not say what you used to measure the voltages with or what the reading were , it is up to you to figure out what those readings mean.
Since I do not have a manual on that motor and it is not a USA model so I cannot even find a parts breakdown of it.

Something has to tell the motor what the throttle is doing to change the timing. I do not think it is magic
All of the old outboards I have seen used mechanical linkage to advance timing plate,
but the newer ones with electronic controlled timing use a Throttle Position Sensor.
According to you, yours has neither.

So maybe someone else will come in and let us both know how timing is advanced on this motor.

WOT is wide open throttle

Re: 9.9 timing issue

Hi Caption, l wish to apologies for my early outburst (l?ll blame the truth syrup) .It was 4am in TAS
If you can explain how to do an attachment l can forward a PDF manual for 9.9hp. The only main difference l can see re- US, is we can alter idle mixture on the carb.
I guess re-timing advance, that this is done by an increase in voltage from the charge coil, as there is no other way it could tell what is making the motor going faster hence needing an increase in spark advance. My readings didn?t change a great deal between working correctly or not, but it has made me have another think re-coils.
Re peck meter? I really don?t know everything, but I?m using a RMS meter which averages out the peaks, would that make difference, from a reading of practical nothing, up to spec?
What is a DVA attachment?
Talking about voltage why are they saying to measure in DCv when flywheel (inductive) type coils are generating AC voltage?
Regards
KD, Tasmania

Re: 9.9 timing issue

Here is some good info to read on troubleshooting CDI systems, http://issuu.com/cdielectronics/docs/troubleshootingguide

that meter will not result in proper voltage readings with out the DVA adapter I know as I tried also. You can buy one on line or find the stuff to make one yourself. kind of a pain to do, but is a simple capacitor device.


The charge coil charges up the capacitor in CDI, caps do not store AC voltage, so they measure the output in DC. Anyway this is my take on that. If you do not measure it the same way they do then the specs mean nothing.

Sorry but I can not believe increase voltage of charge coil advances timing, so still looking for something else. I am not an expert on that motor so maybe some one will help out