2001 200hp hpdi

[Lady E]

Anyone have any experience with removal and replacing a power head on a Yamaha 200HP HPDI ? I have a bad knoc, motor has 1197 hours on it. Compression cold varies between 68 - 90lbs per hole.

Took it to a certified Yamaha mechanic and after 1 1/2hrs and listening to the motor he thought I might have a piece of piston broken off or perhaps a rod bearing bad. To tear down the motor to fully diognose would cost a ton; he thought I should look at getting a new 4 stroke or a new power head. He said the powerhead cost was usually about half the price of a new motor.

My question is, how difficult is it to replace the powerhead? One of my crew members is a professional deisel mechanic but he is apprehensive about taking on the project because he is affraid of the special tool issue and just not knowing what is involved.

Another question is how many hours is a normal life on a HPDI motor with good maintanence? If I replace the powerhead will the lower unit become a problem in the near future?

Thanks In Advance for any advice,

LadyE

[boats.net]

Diesel mechanic shouldn't have any problem replacing powerhead, no special required other a hoist to lift powerhead. Helps to know what caused engine to fail to it doesn't happen to new powerhead. Properly bleeding oil pump and break in is critical on new powerhead replacement if you decide to do work yourself.

[Lady E]

Thank You for the reply. Does 1200 hours seem like a normal time for this kind of failure?

We don't see very many HPDIs in Central Oregon. My local Yamaha mechanic said he had heard that the HPDI series didn't get very many hours before failure; he did say he was not an expert on HPDIs.

Is there any core on the old PH or could I start tearing it down and looking for a reason for the failure?

Thanks Again,

LadyE