HP vs displacement: what does it mean?

[mrr]

Comparing different outboard of 30 HP, weight and displacement differs a lot. Could anyone explain me what does it mean if 30 HP outboards have different displacement?

• Suzuki df30A displacement 490 cc
• Evindrude etec 30 displacement 577 cc
• Yamaha f30 displacement 747 cc
• Honda bf 30 displacement 557 cc

Does it mean anything for the performance/power of the engine?
Will there be a big difference on a zodiac futura MK3?
I just bought the futura and I am interested in the new suzuki DF30a efi.

Thanks a lot!

[beamishken]

The displacement is the volume displaced by the pistons in one revolution
Generaly the smaller the cc then the harder the engine has to work to produce it's rated hp usually achieved by raving the engine a bit harder
With a smaller cc you will usually see a lower max torque produced higher up the rpm range
The benefit of smaller cc is less weight & usually better fuel economy
Personally I think there is no substitute for big cc ' s however it depends on the weight penalty the bigger cc comes with
The yam 30 stands out but it's maybe carries an extra cylinder & possibly a lot heavier
If weight isn't an issue then from that list personally I'd go with the yam