Bob B
Well-known member
Harry,
in the world of continuous duty anything that turns up over 2000rpm is working very hard on the parts. It is the rare piece of aluminum that can take a water pump failure at speed when things are cranked up over 4000rpm. Diesel or gas.
Most of the "High Performance" engines sold are in the 50 hp/liter range and up. In applications where run life is required the range is closer to 25 to 30 hp/liter.
The Hand Grenade term comes from the effect of the pistons and rods when the cooling or oil fails.
I work on diesels and gas inboards, but dont harbor any ill toward outboards, I am just trying to convey some reality into the picture of loading that no salesman or broker is ever going to tell you because they are fearing you will split with your check if you cant go at the pin and get the max speed vs any other choice. I have had customers who could afford new 120 G inboards when the old ones burned up running overloaded.
I think most guys want to get their money out of an expensive pair of motors so the factors of life expectancy as related with loading are important.
As for fuel burn, no doubt the second worst spot from full wide open is just before a hull breaks the bow wave and is ridding right at the end of the displacement spectrum. But slow down and you will make it with the fuel you have, just not fast. (IE, towing insurance claim vs. got home by your own power, but late for supper.)
in the world of continuous duty anything that turns up over 2000rpm is working very hard on the parts. It is the rare piece of aluminum that can take a water pump failure at speed when things are cranked up over 4000rpm. Diesel or gas.
Most of the "High Performance" engines sold are in the 50 hp/liter range and up. In applications where run life is required the range is closer to 25 to 30 hp/liter.
The Hand Grenade term comes from the effect of the pistons and rods when the cooling or oil fails.
I work on diesels and gas inboards, but dont harbor any ill toward outboards, I am just trying to convey some reality into the picture of loading that no salesman or broker is ever going to tell you because they are fearing you will split with your check if you cant go at the pin and get the max speed vs any other choice. I have had customers who could afford new 120 G inboards when the old ones burned up running overloaded.
I think most guys want to get their money out of an expensive pair of motors so the factors of life expectancy as related with loading are important.
As for fuel burn, no doubt the second worst spot from full wide open is just before a hull breaks the bow wave and is ridding right at the end of the displacement spectrum. But slow down and you will make it with the fuel you have, just not fast. (IE, towing insurance claim vs. got home by your own power, but late for supper.)
