Engine maintenance costs
 

Do 496 and 496HO cost more annually to maintain than their 454/502 MAG counterparts?

I currently have a 20' runabout with a 5L V8 and want to get an idea of annual maintenance costs on the engines above. Assume 40-60 hours a year mostly ocean saltwater, work done by certified Mercruiser mechanic.

Chris

Re: Engine maintenance costs
 

Chris,
For the simple reason of the closed cooling on the 496 Mag and HO motors, I would aim that direction. Over the long haul, you will be miles ahead and have a favorable power package for resale in a saltwater market as well.

As far as maintenance, I have twin 496HOs, in a 37' Active Thunder with full 6 year warranties. The 496s are supposed to go 100 hours before you even change the plugs. I took mine to 150 before I did mine. I am now way over that hour mark, with nothing more than annual sea-water pump impellor changes. They are a bulletproof package especially for easy cruising like I do.

As far as fuel; try to contact Dave M here on this site. (I will send him a PM to look at this thread.) He has a 24 Superboat that he went from a 454 to a 496HO. He should have some good direct comparison info for you on fuel. (He has a big propeller on his beanie.)

Re: Engine maintenance costs
 

Maintenance, I would say is not a difference. It's easier to change the oil on my 496 due to the drain tube. The coolant is good for five years, I think. The raw water pump out is nice for early or late in the season.

Fuel consumption, I keep pretty good record of my fuel usage and 496HO burns about 1 GPH more than my 454 mag did.

I'd never go back to full raw water cooling. My 454 Mag with 500+ hours looked pretty ugly inside. I boat in salt or brackish most of the time. I bought the DIACOM software for the PCM555. It's great, I can diagnose problems, check fuel usage, temp, etc. etc.

The 40 extra ponies gave me a solid 3-4 MPH over my old motor. I went from a 26 to a 28 pitch prop, same RPMs.