Does 1hp really make that much difference

[Coontakinta]

My appologies to those of u who have seen this post on another forum, but am keen for input :-[

Does 1hp really make that much difference and how much emphasis should be placed on the torque of a motor?

How much difference in speed would u expect to see between different outboards rated @ the same horsepower on the same hull, given that the actual HP will differ from that of the rated and each will have a different torque rating?

Also would u expect an increase of 850rpm going from a 15" blade to a 14"? :-?

Why does it seem that some outboards can spin 17" blades when others of the same rating cant? Is this down to torque? :-?

Perhaps this is why a torque rating is not listed on the promotional blub! :-/

[fishn-ads]

Can you look up actual KW engine ratings I have noticed some manufactures say one thing on the coweling but the guts of the engine is something different.

Ads

[Spaniard_King]

Each engine would be different, possibly in many ways..ie dissplacement, gear ratio, carby design and inlet air flow for just a few possiblitities

each of these could impact on the performance of the engine.

Also a manufacturer only has to get his engine to within %10 of the desired HP to qualify for that HP. This means x brand may only have 23hp to qualify for the 25hp cateogry. but another brand may have 27hp and chose to put it in the 25hp cateogry.

You would have to dyno each engine to get a true reading

850 RPM with 1 inch pitch change seems a little too much, I would think a 2 inch pitch change for 850 may be more likely.

Garry

[lippa]

this might be a stupid question, but wher can i get my outboard dyno'd. its an '05 merc 60hp.

cheers

lippa

[Spaniard_King]

this might be a stupid question, but wher can i get my outboard dyno'd. its an '05 merc 60hp.

cheers

lippa

Take it to flotsoms place ;)

Seriously lippa, an out board racing team would have the facilities.

cheers

Garry

[lippa]

that bugger is always too pi$$ed to swing a spanner. every time we work on that boat we both end up rolling drunk and acheive f-all!!!! great fun but!!!!!

cheers

lippa

[Spaniard_King]

;D ;D ;D ;D ;D ;D ;D ;D typical Lippa

[Coontakinta]

Actual HP rating

engine #1 88.7 hp
displacement 1267 cc

engine #2 89.8 hp
displacement 1295 cc

I believe engine #2 can spin a 17" blade on boats similar to mine but engine #1 cant. infact it'll only spin a 14" to maximum rpm.

Any ideas?

[Spaniard_King]

What compression does both engines have??

maybe one has a fault

Garry

[krazyfisher]

are the gears the same?
are the props in the same material?
same design prop?
same diameter prop?
same fuel?
same weight in each boat?
there are so many variables.

[Coontakinta]

What compression does both engines have??

maybe one has a fault

Garry

cant tell u Gary as one engine is on the back of the baot waiting to be further checked by the dealer, the other is the one I wish I had bought!