What are symptons of too much carbon build up - Yamaha F150

[dmcelveen]

Can anyone share with me how too much "carbon build-up" will effect the performance of a four stroke outboard? I suspect I may have some carbon buildupin my Yami F-150s. Over the last 4 years I've put 800 hours on the motors with approximatley half of those hours at idle due to drift fishing. I've never used ring free. Thanks for any input you may have.
Doug

[Glen E]

pull a plug - look at the ceramic area - if it is not light tan and clean, and is black or oily - you are carboned up - also inside of prop barrel will be back or oily....

and if you idle a lot - your oil should be changed twice as much - every 50 hours...

[Mr.Chummer]

If your motor has an O2 sensor, that's another check for carbon buildup.


While you're at it, check your compression on the cylinders. Carbon buildup will score your cylinders, especially if it gets into the rings (i.e. ring sticking). Hopefully all of your cylinders are within 5-10% of each other.


Hopefully your motor is clean. If not, Yamaha Ringfree is well worth the money to help save the cylinders and other stuff that can suffer from excess carbon.

[Cracker]

On a 4 cycle if your having any issues of fuel getting into your oil that can be caused by carbon buiold up also... Often reffered to a "making oil"

[dmcelveen]

Thanks for the reponse guys. Can you tell me how the buildup affects the motors performance? I have one motor that is about 300 rpms weaker than the other. I'm wondering if it's cabon buildup that slowed down the motor.