2007 DF 150 makes whirring sound at idle

[BlockIslandguy]

My 400 hour DF 150 has been making a whirring sound at idle, kinda like what a a poorly tensioned fan belt might make on a car. The marina tech says its the counter balancers in the front of the engine. He wants $1300 for the parts and is estimating $1200 in labor. I have looked at the manual and you have to pull the power head to do this work, hence the cost in labor. New counter balancers are about $250 each plus any other parts seals, etc necessary.
I have looked all over the internet for counter balancing problems with Zuks. Nothing, Yahamas certainly but I cannot find anything to lead me to think this could be the problem - it maybe the problem I just dont want to spend $2500 plus without some level of comfort in their diagnosis. Has anyone heard of counter balancing/ chain tensioning issues in a 2007 df 150 or 175?
thanks
Rob

 

[ct1762@gmail.com]

Rob i'm right in Charlestown and can take a look at it when i'm out there in the next 10 days or so.