Testing 0X66 Stator

[chbaker3]

How do you test a stator. I have a 1999 225 OX66. It has weak spark. I did a CDI peak voltage test today and it read 30 volts instead of the 100 at 2000 rpms.

If anyone has any other ideas of what it could be let me know

[99yam40]

input or output of the cdi?
and which coil?

[chbaker3]

It was a CDI output test. I tested all coils. The way I tested them was insert the positive prob into the bullet connector between the CDI and the coil. The negative was grounded. This was done while the engine was running at 2000 rpms.

[rodbolt17]

did you use a peak reading meter like a CD77 or a digital meter with a DVA adapter?
if not your readings will be at least 30% lower than manul specs due to the fact that unless its designed to read voltage PEAK its going to give you working voltage, about .707% of peak.
motor simply wont run if your actual stator output was 30V PEAK. takes about 60V PEAK to allow the ign coil secondarys to arc the plug gap.
any lower and it simply WONT spark.
thats how I know your not using the correct equipment.

[jb123]

weak spark, did you test plug cap resistors ?

[chbaker3]

I retested everything again. I checked to caps and they were all within spec. I rechecked the CDI output with a DVA that is connected to my DVM. All coils had ~450 volts going in.

Yesterday I went pick up some loaner parts. These parts were the whole CDI plate which included the CDI and the 6 coils. I hooked this onto my motor and everything was much better. The CDI output at 2000 was 180 but most important to me was it was not spitting out unburnt fuel like it was before.

I then hooked the coils to my CDI and it jumped to 220 on the output and was sending unburnt fuel out of the exhulst. Today I plan to hook my plate to the CDI and coils and restest. I also plan to retest the O2.

The main reason for me doing this work is due to the engine loading up and not running while in gear in the water.

[rodbolt17]

the ign system on that OX66 is dirt simple.
a pair of coils on the stator charge capacitors in the CDI box, the six pulser coils simply tell the capacitors when to discharge.
the CDI unit does NOT amplify any voltages.
the unburned fuel is typically from a defective fuel pump.
trust me, you NEVER got 450 volts from the stator, aint gonna happen.
peak voltage at the ign coils should be about 130V minimum at 3500 RPM.
the CDI and ECU are one unit,bolts to the rear of the engine.
the pulser coil assy is under the flywheel.
the stator assy contains coils for charging the CDI unit and coils for battery charging.

[chbaker3]

Rodbolt, check out this tread from another site. It explains everything that I have done and results. It is not the fuel pumps. All are new and have been checked for leaks. Same for the injectors.

OX66 flooding - The Hull Truth - Boating and Fishing Forum

[rodbolt17]

can you post the full model number?
then I can explain how the ign system and the fuel system interact on that engine.
like I say, its a dirt simple system

[chbaker3]

it is s225txrx
I do have a firm understanding of how the system works. I have worked on outboards for a while but this one has my mechanic and myself puzzeled

[chbaker3]

I think I have the main problem fixed. I ran it today in the yard and there was no unburnt gas coming out of the exhuslt. I will put it in the water tomorrow or monday and give it a shot.

As for the coils, I was able to fix them without replacing. There was a bad connection between the coil and the wire. I broke the epoxy the test the coil and I had flow. After this I cut about 1 inch off the wire and reconnected and It worked great. I resealed the coil and reinstalled.

Now to work on the top end speed. I am wondering if the TPS is bad. If my memory is correct the max output was only like 3.5 instead of the 5 it should have been.

[rodbolt17]

high idle means the ECU isnt happy or the ECT is bad.
guess what???
on that engine at idle to about 2000 RPM #5 cylinder does not spark.
from about 800 to 2000 #2 does not spark as well.
TPSV at or near wot is about 3.5 to 3.8.
wont ever see the 5V as that is the reference input.
that engine uses the CCS system.
if any sensor fails or the ECT fails to tell the ECU that its above 113*F then timing at idle is locked at about 7*BTDC and high idle speed ocurres.
the O2 sensor is NOT monitored for failure, however if its unplugged the ECU will fix fuel rich at low speed and lean above 4000.
DO NOT opererate above 4000 with the O2 sensor unplugged or high feed back voltage.
if it idles on all 6 cylinders something is broke.
any sensor failures will result in all cylinder operation.
there again, the O2 sensor is an exception.
the CDI assy does NOT step up charge coil input voltage.
whatever is fed to the CDI is fed to the ign coil primaries.
it will run with CDI output voltage as low as 70V peak.
if this thing is idling and your seeing voltage on all 6 ign coil primaries its broke.
only 3 times it sparks on all 6 at an idle,1 is cranking,2 is while warming up and 3 is if its broke.

[chbaker3]

ECT???

I have went through all the sensors and ohmed to tested voltages as the manual says and all checked out well. I will do this again tomorrow.

As far as cylinders firing, I know that 2 and 5 did that. This is why I did all test at 2000 or 3000 rpms. Those 2 cylinders do not fire once the engine is warm and it is idling.

Idle is much better since I fixed the coils.

I will put it in the water tomorrow or monday and check it again.

[rodbolt17]

that engine has an engine coolant temp sensor ECT.
if it doesnt or cannot tell the ECU the engine temp is above 113* the ECU remains in warm up mode, that fixes fuel rich and locks base timing at 7* BTDC and idles high.
top speed can be reached.
if the knock sensor loses its ground or is unplugged timing is fixed at 7* BTDC and top speed cannot be reached.
what the ign timing does can be an indicator of whats hapening.
the diagnostic test lamp would be your friend in this.
if fuel rail pressure increases above 40 PSI it runs pig rich, this can happen if the regulator screen is clogged.

[chbaker3]

I just rechecked the ECT again using the pot of water method. Everything checked out fine. I will not have a chance run the motor today. Also the fuel rail holds 35 psi of pressure.

Is there another way to check the ECT while on the motor running.