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Yamaha OX66 going into slow mode limiter mode

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Yamaha OX66 going into slow mode limiter mode

Old 05-30-2019, 04:59 PM
  #1  
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Default Yamaha OX66 going into slow mode limiter mode

Yamaha 2000 ox66 twin 200HP 26 foot cobia...
What I think is going into slow mode... speed limiters mode... under acceleration (limp mode----Limiting rpm) Cylinder miss fire...under load....canceling cylinders out what ever you may call it!
This happens as soon as I leave the dock.

Here's what I have done so far...
Two years ago pulled off cylinder and cleaned out all cooling passages ( they where about 70% clogged up)
It was going into SLOW mode back then but has been ok till now.
Just trying to give all the history of my motors.
Now just recently I have done a
Compression test all cylinders with in 5% of each other
New spark plus gap to 0.40
New fuel filter and water separator's
New low pressure fuel pumps
Swapped ignition coil from port motor to starboard motor.
Fuel pressure @ 35 psi and steady

Any thoughts will help.
Thank you
MB
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Old 05-30-2019, 05:04 PM
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My 150 ox66's heads were plugged up with crap, as soon as I'd go past a certain RPM, it would go into limp mode. Took the heads off, cleaned everything and it works great now. Not sure if this is your issue, but it was mine.
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Old 05-30-2019, 05:34 PM
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[COLOR=left=#222222]Two years ago pulled the cylinder head off and cleaned out all cooling passages ( they where about 70% clogged up)[/COLOR]
[COLOR=left=#222222]It was going into SLOW mode back then but has been[/COLOR] ok till now.
Good call though...
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Old 05-31-2019, 07:14 AM
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Which gauges do you have
does your alarm work
have you ever checked/replaced waterpump, thermostats, prv

Last edited by wetneck; 05-31-2019 at 08:01 AM.
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Old 05-31-2019, 05:42 PM
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eThe buzzer only work on the port motor as far as the gauge it does not work. only the port side buzzer and gauge work...
I am going to buy a new gauge this week and replace the buzzer for the starboard motor.
I thought that if the buzzer work on my port motor it would also alert me of any over heat or oil level issue with the starboard side.
Am I wrong to think that?

The water pumps pop off valve may have about 40 hours on them.
I am also going to order the diagnostic tool to pull codes ( Winky Blinky)
MB
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