What is displacement, & bore stoke?

[TXredfish]

When looking a outboard information I always stumble around the words displacement and bore and stroke always (measured in inches or mm). Being new to boating and outboards what does it mean?

 

[Bozo]

Re: What is displacement, & bore stoke?

Displacement is the volume the piston "moves" in one cylinder.<br /><br />The bore and stroke make up the displacement. Bore being the size of the cylinder and stroke being the distance the piston moves in the cylinder.<br /><br />If you add up the displacement of all of the cylinders you get the displacement of the engine ie 3.1 liters, ect.

 

[Boatist]

Re: What is displacement, & bore stoke?

TXredfish<br />Bozo discription is correct. It is the size of your engine. Just like your car 4 cylinder are 1.6L to 2.0L. My boat is a I/O and displacement is 181 Cubic Inches or 3.0 Liters and produces 140 HP. Most people do not care much about diaplacement (Bore and srtoke) but do care about HP and Weight. Only time one might look at Displacement would be when comparing two engines of the same Horse Power (HP). Engine with a bigger displacement will probably weigh more and use more fuel but not be working as hard as a engine with a smaller displacement.