Tweet
I am curious as to what actually fails in the rotor and causes it to beat on the crankshaft after a period of time. It is amazing that Yamaha can't seem to overcome this issue with this flagship engine.
-
-
It is my understanding that excessive temperature is causing the rubber in the flywheel/rotor/damper to fail prematurely. The damper function fails and over time the crank shaft can break. It is particularly prone to failing the crank shaft if and when the motor is run in a particular RPM range.
Yamaha is providing free flywheels at no charge for all V8 F300's/F350's, over and over again as needed. A new ECU is also provided that logs time in the RPM band that is problematic. When the ECU sees X number of hours in that band then it sets a fault code. The code tells the mechanic that it is time for a new rotor/flywheel/damper.
It does seem that by now Yamaha would have come up with a permanent solution. However, there are some airplane motors that have a similar type of problem. There are restrictions telling the pilot to stay out of a particular RPM range when cruising. He can pass through the range but is to not operate the motor continuously within the specified range.
https://en.wikipedia.org/wiki/Harmonic_balancer
Crankshaft Harmonic Dampener/Balancer Failure Signs -
Don't usually send links to other forums, but here goes some good info on this.Originally posted by pstephens46 View Post
http://www.thehulltruth.com/boating-...n-problem.htmlChuck,
1997 Mako 191 w/2001 Yamaha SX150 TXRZ Pushing HerComment
-
Thanks Chuck. I tried to weed through a few of these THT threads too. It seems the facts may be related to separation of the flywheel, dampener and such. There was a good pic on the link you sent. Maybe these motors need the balancer shafts more so than the F150.Originally posted by cpostis View PostComment
Comment