Need specs on Eska 1974a 4,5 Hp!

[EskaMan]

Hello!

I'm in 2. year of mechanical engineering and are doing a project on a 1975 - Eska 1974a - 4,5 Hp Outboard.

I' m supposed to dimension some of the moving parts inside and to do this i reeeeeeeally need to know the thrust of the propeller!

It's a 2-blade but i dont know area, diam or pitch... I found the op-manual for the 7,5 Hp, but that doesnt do me any good

Can anybody help me with info on this engine? Or have a common thrust i can assume it should handle? ANY info is much appreciated!

Tnx

 

[steelespike]

Re: Need specs on Eska 1974a 4,5 Hp!

The 1974A has a Tecumseh AV520 powerhead 2.09 bore X 1.50 Stroke.
5.16 cu. in.I couldn't find the propeller sizes.You can measure the diameter
simply across tip to tip on the blades.Look carefully all over the prop for numbers something like 6" X 6 " (diameter by pitch).pitch is the distance
prop would move through water in one revolution disregarding any slip.
You might find some prop demensions at Sears parts using Eska built Sears motor model number 217-59464. Thats for a 74 4.5 motor specs will be the same. You won't find thrust info for any outboard Except possibly electric trolling motors My guess is a 4.5 would push a lightly loaded small boat at 8 to 10 mph.

 

[EskaMan]

Re: Need specs on Eska 1974a 4,5 Hp!

Tnx mate. I actually knew the cylinder specs, but the serial you gave me might just do the trick. Any good reason why thrust is never specified on outboards? I would persume it would be more useful than engine hp. Could anybody give me a number for the thrust? I mean, is it 100 N or 2000 N? I really have not got a clue to what it should be.

 

[steelespike]

Re: Need specs on Eska 1974a 4,5 Hp!

Unfortunately I've never seen any thrust numbers for outboard motors
and you very seldom see any torque figures.
There are electric outboards that are rated by horsepower
Some of which may give thrust figures.If you do a search on the net for electric boats,electric outboards you may find some comparisons.There are a few electric trolling motors that are rated by hp and possably thrust
I do believe a reasonably strong man with good support could hold your 4.5 still with some sort of grip like a Ski rope.But I don't believe it would be a goods indication because I think being stationary would introduce excessive slip.