inpropsicated

A friend of mine is looking into getting a new boat. It has a 496 HO I/O and we are debating the expected life of that motor. It seems to have it's best cruise around 4k RPMs. I know that there is a lot that drives all of this but for conversation, lets keep things simple. Here is a basic list of assumptions:

Pushes a 26' Sonic (single engine install).
Makes routine oil changes and servicing.
Runs in brackish water at 4,000 RPM as normal cruise.
Makes no aftermarket engine or drive modifications.

My guess is around 300 hours. What are other peoples thoughts or experiences?

BillR

Your hour estimate is way low. I know people that have 300 hours on the motor, and it still runs like a top.
My best guess would be 1500+ hours.

CigDaze

1000+ hours easily!!

In its stock condition, with routine fluid changes and flushes, that engine will run seemingly forever.

I know many people with close to 1000 hours with no noticible performance loss.

It all comes down to care and maintenance.

Kentz

Agree! you don't even pull a plug to inspect until 300 hrs. ? isn't 4k cruise a little high in a 26 sonic?

inpropsicated

That puts a cruise about 45-50 MPH at 4k RPM. All these numbers are really surprising me since it is at such a high RPM rate. I would think that an engine that large could not handle 4k RPMs for that long of a period of time. That is a lot of metal moving around where things can go wrong or break loose. But then again, it is below the 1:1 ratio (cubic inch to HP).