Re: Engine Boring Definition
Boring the cylinders out can be a reconditioning method to give new walls to worn or scored cylinders. This can be a very small increase and would not change performance measurably. It can also be done to increase the "bore" significantly to result in increased overall "displacement" which is the size of the void left in the cylinder when the piston is all of the way down, then times the number of cylinders. If you add a "stroked" crank you increase the displacement even more. Anytime you increase displacement, you also increase available air. More air equals more potential for more fuel which is potentially more power. This does not automatically mean worse or better fuel economy although typically, as you increase displacement, the engine must be throttled more (more of a closed throttle), so for the same load (your boat at a given speed) you have increased throttling losses and you should get worse fuel efficiency. This is theoretical, and seems bass ackwards, but it's accurate.
